Slice each chicken breast in half horizontally to make four thinner pieces; pat dry and season both sides with salt, garlic powder, black pepper, oregano, and chili powder.
Heat 1 tablespoon olive oil and 2 tablespoons of the butter in a large skillet over medium-high heat until hot.
Add the chicken pieces to the skillet and cook 4–5 minutes per side, until browned and cooked through (internal temperature 165°F/74°C).
Remove the cooked chicken to a plate and reduce heat to medium; add the remaining 2 tablespoons butter, minced garlic, Italian seasoning, and crushed red pepper to the pan and cook, stirring, about 1 minute until fragrant.
Add the broccoli florets and the water or chicken stock to the skillet, then add lemon juice; cook 2–3 minutes, stirring occasionally, until broccoli is bright and just tender.
Return the chicken to the skillet, toss with the garlic butter and broccoli to coat, heat through for 1 minute, then remove from heat and serve immediately.