Boil salted water, cook pasta until al dente (8–10 mins), drain, set aside.
Season chicken with salt and pepper. Sear in 1 tbsp olive oil over medium-high heat, 4–5 mins per side. Rest, then dice.
Lower heat, melt 2 tbsp butter. Add minced garlic, sauté 1 min. Stir in 1 tbsp flour for 1 min.
Slowly whisk in 1¼ cups heavy cream + ½ cup pickle juice. Simmer 2–3 mins.
Stir in ¾ cup parmesan, 1 tsp dried dill, ½ tsp black pepper. Adjust salt if needed.
Add diced chicken and ½ cup chopped dill pickles. Simmer 2 mins.
Toss pasta in sauce until coated evenly.
Serve warm with extra parmesan and fresh dill on top.