Cook Noodles: Cook the noodles in salted water according to the package directions. Drain.
Heat Grill: Heat the grill to high heat.
Roast Chiles: Grill the chiles on the grill for 4-5 minutes per side until tender. Place in a plastic bag for 2-3 minutes. Remove skins, stems and seeds and chop.
Mix: In a large 13 x 9 pan, combine the cooked noodles with the seasonings, 1 1/2 cups of cheddar cheese and the roasted chiles. Stir in the Velveeta and cream cheese. (It's a little easier if you use your hands)
Add Milk: Pour 1 cup of milk on top, distributing evenly across the pan.
Adjust Grill: Adjust the heat of your grill or smoker to 250F degrees with an indirect heat zone.
Smoke: Smoke at 250F degrees for 20 minutes. Stir. Smoke 20 more minutes. Stir again.
Add Milk: Pour 1 cup of milk evenly over the pan. Top with 1/2 cup cheddar cheese. Smoke for 10 more minutes until brown and bubbly.
Rest: Let rest for 10-15 minutes. The milk will continue to absorb into the noodles during the resting stage.
Notes
Instead of roasting your own chiles, you can also use 1/2 cup of canned or frozen green chiles.