Thaw scallops, if frozen. Halve any large scallops. Cut about a quarter of the mango into 1/2-inch cubes; set aside. Place remaining mango into a blender with pineapple juice. Cover and blend until smooth. Divide pureed mango mixture into eight shot glasses; set aside.
In a small bowl combine agave, ground chipotle chile pepper, and coriander. Pat scallops dry with paper toweling. Brush scallops with the agave mixture. Sprinkle lightly with salt and pepper. In a large nonstick skillet cook scallops in hot butter over medium-high heat for 2 to 3 minutes or until opaque and golden, turning halfway through. Remove scallops from skillet; insert a toothpick into each. Thread 1 or 2 cubes reserved mango onto top of each pick.
Pour about 2 teaspoons tequila over mango puree in each shot glass. Add 1 scallop-mango pick to each shot glass.