In a large ziplock bag, combine the ranch dressing packet and olive oil. Shake to combine.
Add the potatoes to the mixture and close securely before shaking.
Cut 4 large pieces of tinfoil and divide the potatoes evenly between the four.
Top each potato packet with a fourth of the cheese.
Pull up the long ends and meet in the middle, then fold down. Fold the ends closed tightly.
Preheat the grill to 350° on medium heat.
Place the foil packets, seam side down. Grill for 10 minutes, then flip over.
Grill an additional 7 to 10 minutes.
Remove and carefully open and enjoy.
Top with chives, sour cream, bacon, ham, salsa, or broccoli.