Heat 1 tbsp olive oil in a large skillet over medium-high heat until hot.
Add the sliced red, green, and yellow bell peppers and the sliced yellow onion; cook, stirring occasionally, until slightly charred and beginning to soften, about 3 minutes.
Stir in the diced cooked chicken, 1 tsp chili powder, 1 tsp garlic salt, and 1 tsp ground cumin.
Squeeze the juice of 1 to 2 limes over the mixture and toss to coat; cook just until the chicken is heated through and flavors are combined, about 1–2 minutes.
Meanwhile, divide the 4 cups of cooked rice among 4 bowls.
Top each bowl of rice with the fajita chicken and vegetables, then add sliced avocado, diced tomato, shredded cheese, sour cream, chopped cilantro, and lime wedges as desired.
Serve immediately and enjoy.