Pesto Chicken Philly Melt

Ingredients

• 1 boneless, skinless chicken breast
• 1 1/2 tbsp balsamic vinegar
• 1/4 cup olive oil
• 2 cloves garlic, minced
• Montreal steak spice
• 1/4 green pepper, sliced
• 1/4 red pepper, sliced
• 1/4 onion, sliced
• pinch of oregano
• 2 tbsp pesto
• 1 tbsp mayonnaise
• 1 tbsp jalapeño peppers, chopped (optional)
• 1 Ciabatta bun
• 3 slices 2 year old Bothwell cheddar
• lettuce, shredded
• 3 tomato slices