Whisk together Greek yogurt, olive oil, lemon juice, paprika, chili powder, garlic, salt, and pepper to create the marinade.
Add chicken to the marinade, coat well, and marinate for at least 30 minutes or up to 4 hours.
Boil baby potatoes in salted water for 10 minutes until fork-tender, then drain and pat dry.
Toss potatoes with olive oil, salt, and pepper; set aside.
Grill or sear the marinated chicken over medium-high heat for 5–6 minutes per side until cooked through and charred.
Let the chicken rest before slicing.
Crisp the baby potatoes in a hot skillet or under a broiler until golden and crispy, about 10–15 minutes.
In a bowl, mash feta cheese and mix with sour cream or Greek yogurt, fresh dill, lemon juice, and optional pickles or capers until creamy.
Serve sliced chicken topped with dill feta cream alongside crispy baby potatoes. Garnish with extra dill or lemon zest if desired.