On a large griddle over medium heat, cook bacon until crisp, 8 to 10 minutes, turning once. Drain on paper towels. Pour off fat and set it aside.
Whisk flour, sugar, salt, baking powder, baking soda and chives. In a blender, mix buttermilk, butter and 1 cup peas. Add egg; pulse to combine. Fold buttermilk mixture into dry ingredients until just combined. Fold in remaining 1/2 cup peas. If batter is too thick, add 1 Tbsp. milk.
Warm griddle over medium heat; grease with 2 tsp. reserved bacon fat. In batches, drop 1/4 cupfuls of batter onto griddle. Cook until undersides of pancakes are golden, 2 minutes. Flip pancakes with spatula and cook 2 minutes more. Serve pancakes with bacon broken into smaller pieces, sour cream and more chives, if desired.