These nibbles can be prepared in quantity without much fuss.
Preheat oven to 400 degrees. Lightly coat four 12-cup or two 24-cup mini muffin tins with cooking spray; set aside. Whisk eggs, salt, pepper, and chives in a large bowl; set aside. Put 1 zucchini round, 1 mushroom slice, and about 1 teaspoon bell peppers into each muffin cup. Ladle egg mixture into each cup to fill; sprinkle with cheese, dividing evenly. Bake until set, 8 to 10 minutes. Serve warm.