Preheat your oven to 375 degrees Fahrenheit. Place two large chicken breasts between parchment paper and flatten with a mallet. Place on a parchment-covered sheet pan.
Mix together the olive oil, chili powder, paprika, garlic powder, onion powder, cumin and salt in a small bowl.
Slice red onion and yellow bell pepper and place on the sheet pan. Pour the chili mixture all of the chicken and vegetables.
Roast in the oven for 15 minutes, then flip over the chicken and stir in the cauliflower rice. Roast for an additional 15 minutes.
Remove the chicken, onions and peppers from the pan and cut into cubes. Toss the cubes with salsa verde, then arrange the chicken and cauliflower rice on a plate. Top with cilantro, additional salsa and cheese if desired!