Combine the spices - chili powder, cumin, oregano, salt and pepper into a small bowl and mix well to incorporate.
Start by seasoning the chicken pieces with 3/4 of the seasoning mix. Reserve 1/4 for seasoning the vegetables.
Heat 1 tablespoon olive oil over medium heat in large skillet. Add the chicken and cook for about 8 - 10 minutes, stirring frequently until the chicken is no longer pink and cooked through.
Remove the chicken from the pan and reserve it on a plate.
Add 1 tablespoon olive oil to the skillet and add the peppers and onions. Saute the vegetables over medium-high heat until softened and slightly charred.
Meanwhile - heat a grill pan over medium heat to toast/char the corn on the cob. Add the corn to the pan and rotate frequently until it's slightly charred on all sides - about 10 - 15 minutes. Once the corn is grilled, cut the corn off the cob, using a sharp knife and reserve the kernels in a bowl as a topping for the fajita bowls.
Cilantro Lime Rice
Prepare the rice according to package drections. Once the rice is cooked, add the butter, green onions, cilantro, lime juice and lime zest. Stir until incorporated.
To prepare the bowls, layer some cilantro-lime rice, chicken, sauteed veggies, black beans, grilled corn and sliced avocado.