Melt butter, and sauté onion and garlic in medium nonstick skillet for 2-3 minutes until onion is translucent. Add flour to pan and stir; cook flour 2-3 minutes until light golden color and bubbling. Then add bouillon and evaporated milk and mix to combine. Sauce will thicken. Add chicken and vegetables. Season with salt and pepper and cook 3-4 minutes until vegetables are cooked through. Turn off heat and set aside.