Heat 2 tablespoons olive oil in a large skillet over medium heat.
Season diced chicken with salt, pepper, garlic powder, and paprika.
Cook chicken in skillet for 6-8 minutes until browned and cooked through; remove and set aside.
In the same skillet, add remaining 2 tablespoons olive oil.
Sauté diced onion for 2-3 minutes until softened.
Add minced garlic and cook 30 seconds until fragrant.
Add cauliflower rice, season with salt and pepper, and cook 5-7 minutes until tender, stirring occasionally.
Prepare pesto by pulsing basil, Parmesan, pine nuts, and garlic in a food processor until finely chopped.
With processor running, gradually add olive oil until desired consistency is achieved; season with salt and pepper.
Return cooked chicken to skillet with cauliflower rice and stir to combine.
Pour pesto over chicken and cauliflower rice; stir to coat evenly and cook 2-3 minutes to heat through.
Serve warm, garnished with fresh basil leaves and additional Parmesan if desired.