In a Dutch oven or large pot, heat 2 tablespoons of olive oil over medium-high heat. Add sliced red onion and 3 minced garlic cloves. Sauté until the onion is translucent, about 5 minutes.
Add two tablespoon of butter, a pound of bone-in chicken, sliced fresh corn, cilantro, and chicken broth. Bring to a boil and cook covered, on medium heat, 20-30 minutes.
Transfer the chicken to a plate. Discard the skin and bones. Chop or shred the meat and return it to the pot. Add one can of sweet corn and the canning liquid. Stir in the cup of milk; simmer for 10 minutes.
Season the soup with ½ tablespoon each salt and pepper. Toss in one cup of corn tortilla chips and stir to combine and soften the chips.
Using an immersion blender, puree some of the soup to thicken to a chowder consistency (avoiding the fresh corn). Alternatively, ladle some of the soup into a food processor or standard blender, puree it, and return to the pot.
Serve the chowder topped with some of the remaining chips and cilantro. Sprinkle with feta cheese and hot sauce if desired.
For a shortcut, and to omit the shredding later, add cut boneless, skinless chicken dark meat to the soup. However, I highly recommend bone-in and skin-on meat, as it intensifies the flavor of the chowder.
For the same reason I don't suggest using rotisserie chicken, but you can try if you only have 15 minutes to cook.
Remove the chicken [and fresh corn] right before the last step - blending the soup (what I should've done facepalm). Blend, then return the corn pieces and shredded chicken.
Serve the chowder with hot sauce and top with feta if desired (*see variations in the post).