Pat the chicken dry and, if using breasts, slice them in half horizontally to create thinner pieces; set aside.
In a small bowl, combine paprika, garlic powder, onion powder, oregano (or Italian seasoning), salt, and pepper.
Season both sides of the chicken with the spice mixture.
Place the trimmed green beans in a microwave-safe dish with 1/2 cup water and microwave on high for 8 minutes, then drain.
Heat the butter and avocado oil in a large heavy-duty skillet over medium heat until the butter melts.
Add the chicken and cook about 5 minutes per side, or until cooked through and the internal temperature reaches 165°F (74°C); remove chicken and set aside.
Add the minced garlic, Sriracha or sweet chili sauce (if using), and crushed red pepper flakes (if using) to the same skillet and sauté for about 1 minute until fragrant.
Stir in the microwaved green beans, chicken stock, and lemon juice; simmer for about 5 minutes until the beans reach your desired tenderness and the sauce reduces slightly.
Push the beans to the side, return the chicken to the skillet to warm and coat with the sauce, then serve.