Bring large pot of water to boil over high heat. Preheat oven to 375 degrees. Lightly grease oval (or 9x13) casserole dish and set aside.
Add egg noodles to boiling water and stir. Cook according to package directions until al dente. Drain and set aside.
While noodles are cooking, melt butter in large pot over medium to medium hight heat. Saute onion 3 minutes or until it starts to turn translucent. Stir in corn and green chiles. Add in flour and whisk to incorporate. This will take a good 30 seconds of stirring. Slowly whisk in chicken broth to ensure a smooth sauce.
Whisk in taco seasoning, salt (if desired) and pepper. Boil to thicken, then reduce heat to low. Stir in half & half. Taste and adjust seasonings.
Add egg noodles, black olives and half of the cheese into the sauce. Stir in chopped chives and/or cilantro if desired. Add the chicken.
Pour into prepared casserole dish. Top with remaining cheese and bake 10 minutes or until hot and bubbly.
Remove from oven, sprinkle crushed corn chips over the top and garnish with chives and/or chopped cilantro. Serve immediately.