Mix together the salt, ground black pepper, garlic powder, and onion powder.
Sprinkle the seasoning mix onto the chicken.
Heat 3 tablespoons olive oil in a large skillet or 6 qt size dutch oven. Add the chicken and cook until browned on both sides and cooked through. Remove chicken from pan and set aside.
Using the same pan as the chicken, use the last tablespoon of olive oil and cook the mushrooms until they are soft, about 3-4 minutes.
Add the garlic and cook until fragrant, about 1-2 minutes.
Pour in 1/4 cup white wine and cook until it's reduced by about half, about 3-4 minutes.
Add the spinach and cook just until wilted, about 2 minutes.
Still in half and half, mustard, and grated cheese.
Fold the chicken into the sauce and cook until sauce and chicken are heated through, about 2-3 minutes.
Serve 1 cup dijon chicken with 1 cup angel hair pasta.