Clean, dry, and tear radicchio leaves into bite-size pieces. Peel and remove pith from oranges, slice into segments, and reserve any juice. Toss orange segments with radicchio. Whisk olive oil with white wine vinegar and reserved juice from orange. Drizzle over radicchio and orange segments. Season with salt and pepper and toss to combine. Top with toasted pine nuts.
Serve fresh alongside Chicken Cacciatore (see recipe) with crusty bread.