Zest the lime to get 1/4 teaspoon zest and juice it to yield 2 tablespoons juice; set aside.
Preheat the oven to 400°F and arrange a very large sheet pan or two smaller pans.
Make the cilantro-lime sauce: combine 1/2 cup cilantro, 1/2 tablespoon minced jalapeño, 1/4 cup mayo, 1/4 cup sour cream, 1/2 teaspoon minced garlic, the lime zest and juice, 1/4 teaspoon salt, and 1/8 teaspoon pepper in a food processor or blender; blend until smooth, then refrigerate.
Dice the onion and mince the garlic for the filling.
Heat 1 tablespoon olive oil in a large cast-iron or heavy skillet over medium-high heat. Add the diced onion and cook 3–5 minutes until soft and translucent.
Add 2 teaspoons minced garlic and cook 20–30 seconds, then stir in chili powder, cumin, paprika, onion powder, garlic powder, oregano, 1/2 teaspoon salt, 1/2 teaspoon pepper, and 1/2 tablespoon chicken bouillon powder; cook 30 seconds until fragrant.
Push the aromatics to the pan edges, add 1 pound ground chicken to the center, crumble, and cook about 4–5 minutes until no longer pink (drain excess liquid if needed).
Stir in 1/2 cup tomato sauce and scrape any browned bits from the pan; simmer 3–5 minutes until fully cooked through, then remove from heat.
Place the stand-up corn tortillas on the prepared pans (fit 9–10 in a 9x13 and the remainder in an 8x8) and bake 5 minutes to prevent sogginess.
Fill each baked shell with a heaping 1/4 cup of the chicken mixture and about 2 tablespoons shredded cheese on top.
Bake the filled tacos 8–15 minutes until the shells are crispy and the cheese is thoroughly melted.
Top with desired toppings and the cilantro-lime sauce, then serve immediately.
