Creamy Chicken Florentine Pasta

Name: Creamy Chicken Florentine Pasta
Ingredients: 1 pound chicken tenders (or chicken breasts cut into 1-inch strips); 1½ teaspoons garlic powder; 1 teaspoon Italian seasoning; ½ teaspoon kosher salt; ½ teaspoon freshly ground black pepper; 2 tablespoons olive oil; 2 tablespoon butter; 8 oz linguine pasta (or other shape as desired); 1 small onion (diced (about 1/2 cup diced)); 3 garlic cloves (finely chopped (about 3 tablespoons)); ½ teaspoon red pepper flakes (more or less to taste); 2 tablespoons all-purpose flour; ¼ cup white wine; 1½ cups chicken broth; 2 teaspoons dijon mustard; ½ cup heavy cream; 2 teaspoons lemon juice (more or less to taste); ½ teaspoon kosher salt (more or less to taste); ½ teaspoon freshly ground black pepper (more or less to taste); 6 oz baby spinach (coarsely chopped); parmesan cheese (for topping)