When it comes to fuss-free weeknight dinners, it’s hard to beat this Chicken Fajita Casserole – it’s quick, cheesy, family-approved, and made with just 5 simple ingredients. All the classic fajita flavours you love, baked together in one dish. Dinner. Sorted.
If you love recipes that are big on flavour but low on effort, make sure you check out my Mexican Lasagne with Tortillas or my 4-ingredient Mexican Salsa Chicken too!
This is the kind of dinner I pull out on those nights when I really don’t feel like cooking—but still want to put something warm, filling and delicious on the table. You get all the flavour of classic chicken fajitas, minus the wrapping, flipping, or stovetop mess.
Just toss your chicken, capsicum and onion with seasoning, sprinkle on cheese, bake, and serve. It’s perfect with rice, wraps or just a big dollop of guac on the side. And the fact that it’s made in just one dish? Mum win.
Plus, it’s customisable (add beans or corn to stretch it further!), freezer-friendly, and a guaranteed hit with the kids. If your family loves this, they’ll also enjoy my One Pot Taco Pasta or Slow Cooker Mexican Chicken Soup.
Why You're Going To Love This Recipe
- Just 5 ingredients – No long shopping lists here!
- One dish dinner – Less washing up, more relaxing.
- Kid-friendly – Even the fussiest eaters get on board with cheesy chicken.
- Ready in 30 minutes – Perfect for those busy weeknights.
- Versatile & customisable – Add your favourite toppings, sides or extra veg.
Jump to:
Casserole Ingredients
This recipe is made using everyday supermarket ingredients—nothing fancy or hard to find!
Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method.
- Chicken breasts – Boneless, skinless breasts work well, or you can use tenderloins or thighs if preferred.
- Fajita seasoning – A store-bought sachet makes this extra easy, but homemade works too.
- Grated cheese – I use a Mexican blend with cheddar and mozzarella for that perfect melty finish.
Variations
- Gluten-free – Just check your seasoning sachet is GF.
- Low carb – Serve with cauliflower rice or salad.
- Add-ins – Stir through corn, black beans, or zucchini before baking.
- No cheese? – Skip it and top with salsa or guac instead.
- Serving ideas – Spoon into tortillas, serve with rice, or load up with sour cream, guacamole, and fresh coriander for a full Mexican-style feast.
How To Make Chicken Fajita Casserole
Let’s make a chicken fajita casserole - packed with all the bold, sizzling flavours you love from your favourite Mexican restaurants!
Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method.
- Step 1: Slice the chicken into strips and toss with olive oil and half the seasoning. Place into the baking dish.
- Step 2: Add capsicum and onion, sprinkle over remaining seasoning, and toss to coat. Spread into an even layer.
Bake for 15 minutes.
- Step 3: Sprinkle over cheese and return to the oven for another 10–15 minutes, or until cheese is melted and bubbly, and chicken is cooked through.
Top Tip
Slice your chicken and veggies evenly so everything cooks at the same rate and you don’t end up with dry chicken pieces or crunchy onion!
Recipe Tips
- Use a large baking dish so the ingredients roast instead of steam.
- Slice evenly for even cooking and juicy chicken.
- Don't skip the cheese – it helps lock in moisture and adds that delicious golden topping.
- Meal prep friendly – prep ahead and store covered in the fridge before baking.
- Leftovers? Store in the fridge for 2 days or freeze in an airtight container for up to 2 months.
- To reheat – Microwave or oven-bake until the centre is piping hot.
- Want more heat? Add chilli flakes or sliced jalapeños before baking.
- Garnish it up – Fresh coriander, lime wedges, or sour cream make it pop.
Chicken Fajita Casserole FAQs
Yes, taco seasoning will work—though it’s usually a little more cumin-heavy and less smoky.
Yes! You can prep everything in the baking dish (minus the cheese) and keep it covered in the fridge for up to 24 hours. Add the cheese and bake when ready.
The chicken should be completely white in the centre with no pink, and juices should run clear. For extra certainty, use a meat thermometer – it should reach 75°C (165°F).
Of course! Zucchini, mushrooms, corn, or cherry tomatoes are all great additions – just keep the total quantity in check so the dish doesn’t become too watery.
Simply mix chili powder, smoked paprika, cumin, garlic powder, onion powder, oregano, salt, pepper, and a pinch of cayenne. Store in a jar and use 2 tablespoons per 500g of meat or veg. It’s perfect for quick, flavour-packed dinners!
More Easy Family Dinners
If your family loved this Chicken Fajita Casserole, try these next:
Let me know in the comments if you give this one a go—I’d love to hear how your family enjoyed it! And don’t forget to tag me if you share it on socials 📸🧡
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Chicken Fajita Casserole
Ingredients
- 600 g chicken breasts, skinless (approx 2 large) or thighs or tenderloins
- 40 g sachet fajita seasoning
- 2 medium capsicum sliced (or 3 small)
- 1 onion brown or yellow, sliced
- 150 g grated Mexican cheese blend cheddar & mozzarella (see notes)
Instructions
- Preheat oven to 180 degrees celsius (fan-forced). Grease a 20cm x 30cm (8" x 11") baking dish and set aside.
- Cut the chicken breasts into smaller pieces (approximately 3-4 strips per chicken breast) and coat with 1 tablespoon of olive oil and half of the fajita seasoning. Place into the prepared baking dish.
- Add the sliced capsicum (bell peppers), onion and the remaining fajita seasoning. Toss until well coated and then spread the ingredients out evenly in the baking dish.
- Bake for 15 minutes then remove from the oven and sprinkle with grated cheese. Return to the oven and bake for a further 10-15 minutes or until the cheese has melted and the chicken has cooked through.
Notes
- Slice your chicken and veggies evenly so everything cooks at the same rate and you don’t end up with dry chicken pieces or crunchy onion!
- Use a large baking dish so the ingredients roast instead of steam.
- Slice evenly for even cooking and juicy chicken.
- Don't skip the cheese – it helps lock in moisture and adds that delicious golden topping.
- Meal prep friendly – prep ahead and store covered in the fridge before baking.
- Leftovers? Store in the fridge for 2 days or freeze in an airtight container for up to 2 months.
- To reheat – Microwave or oven-bake until the centre is piping hot.
- Want more heat? Add chilli flakes or sliced jalapeños before baking.
- Garnish it up – Fresh coriander, lime wedges, or sour cream make it pop.
Lucy says
A family favourite in our house! We serve it with plenty of corn chips, guacamole and sour cream!