Pepper Jack Guacamole Burgers

• 1 tablespoon neutral oil, such as grapeseed, plus more for brushing the grill
• 1 1/2 pounds ground chicken (preferably 1 lb white meat plus 1/2 lb dark meat)
• 1/2 cup shredded pepper jack cheese
• 1/4 cup finely chopped scallions, white and green parts (from about 2 scallions)
• 1 teaspoon garlic powder
• 1/2 teaspoon ground cumin
• 1/2 teaspoon salt
• 1/4 teaspoon freshly ground black pepper
• 4 toasted rolls

For serving:

• Lettuce, guacamole, sliced red onion, sliced tomato (you can substitute fresh pico de gallo)