Preheat your oven to 350°F. While the oven heats, prepare all your ingredients: cut the chicken into 1-inch thin strips, deseed the bell peppers and slice them into 1/2-inch wide strips, slice the red onion, and mince the garlic cloves. Having everything prepped and ready before you start cooking makes the process much smoother and ensures even cooking throughout the dish.

In a large mixing bowl, combine the chicken strips, sliced peppers, and onions. Pour in the olive oil, fresh lime juice, and sprinkle the fajita seasoning and dried oregano over the mixture. Add the minced garlic. Toss everything together thoroughly, making sure each piece of chicken and vegetable is well coated with the oil and seasonings. This creates an even distribution of flavors that will develop as the dish cooks.

Spread the seasoned chicken and vegetable mixture evenly across a lightly oiled baking sheet in a single layer, ensuring nothing is crowded or stacked. Roast in the preheated 350°F oven for 10 minutes, then remove from the oven and stir the mixture to ensure even cooking and browning. Return to the oven and bake for an additional 5 minutes until the chicken is cooked through and the vegetables are tender. I like to give it a good stir halfway through because it helps the chicken brown on all sides and prevents the peppers from getting too soft on one side.