Combine pickle juice, milk, and Greek yogurt or buttermilk in a bowl until blended well.
Add chicken pieces to the marinade, fully cover, then refrigerate for at least 30 minutes or up to 4 hours for stronger flavor.
In a small bowl, mix salt, pepper, paprika, garlic powder, onion powder, and cayenne pepper to create the seasoning blend.
Remove chicken from marinade and thoroughly pat dry with paper towels to ensure a good sear.
Drizzle olive oil over the chicken and toss with the prepared seasoning so all pieces are evenly coated.
Heat a grill pan or non-stick skillet to medium-high and lightly oil the surface with cooking spray or olive oil.
Place chicken chunks in a single layer and grill each side for 3 to 4 minutes until nicely browned with grill marks and cooked through to 165°F (74°C).
If needed, cook the chicken in batches to avoid overcrowding and achieve even cooking.
Transfer cooked nuggets to a plate and let them rest for a few minutes to keep them juicy.
For an extra authentic touch, brush the grilled nuggets with melted butter immediately after cooking to boost richness and flavor.
