Brush olive oil on one side of both slices of bread and place oil-side down on a cutting board. Top each slide with half the cheese and brush honey mustard on top. Layer chicken, avocado, and bell pepper on top of one piece of bread, then top with other piece. Place sandwich in a pan over medium-high heat and place a plate on top to act as a weight. Turn the heat down to medium after a minute and cook for 2 to 4 minutes on each side, checking every minute or so, until melted to your liking.
Nutrition score per serving: 511 calories, 22g fat, 30g carbs, 46g protein