Set Instant Pot to sauté mode. Sauté onion for 4 minutes. Add chicken, smoked paprika, Italian seasoning, kosher salt, pepper, and garlic; stir to coat chicken. Add water, bouillon cubes, and lemon juice. Add rice; do not stir. Seal and set to manual setting for 22 minutes. Natural release for 10 minutes, then quick release. Stir in remaining ingredients.