Combine the chicken, cilantro, sour cream, chipotle, adobo sauce, lime juice and zest, jalapeño, and salt in a bowl until combined. Cut each tortilla in half, then arrange about 3 tablespoons of the filling at the widest part of each tortilla and roll into a cylinder; secure each cylinder with a toothpick. 

Heat 1 inch of oil in a skillet until it reaches 350°F on a candy thermometer or a piece of white bread sizzles and turns golden when put into the oil. Carefully put the taquitos in the hot pan so the toothpicks are facing up. Fry the taquitos until golden on the bottom, then remove the toothpicks, flip, and finish cooking, 2 to 3 minutes total.

Preheat the oven to 375°F. Arrange the taquitos on an ovenproof plate or baking sheet and top with cheese. Bake until the cheese is melted and bubbly, 5 to 6 minutes.

Combine the avocado, tomato, pickled jalapeño, onion, and cilantro and scatter the topping over the taquitos. Remove the taquitos from the oven, top with the topping, dollop with sour cream, and serve.