Step 5
Meanwhile, heat remaining 2 Tbsp. oil in a large skillet over medium-high. Cook onion, stirring, until softened, 3–4 minutes. Add garlic and cook until fragrant, about 1 minute more. Add marinara sauce, red pepper flakes (if using), 1/4 cup basil, and remaining 1/2 tsp. oregano, 1/4 tsp. salt, and 1/4 tsp. pepper. Cook, stirring until sauce starts to bubble. Reduce heat to medium and simmer until chicken is ready, stirring occasionally, at least 5 minutes.