How to Make It
Combine vinegar, oil, and radicchio in large bowl; toss. Let stand 10 minutes.
Heat a grill pan over high. Coat pan with cooking spray. Add radicchio to pan (do not discard vinegar mixture). Grill 4 minutes or until lightly charred. Remove stem ends; discard.
Stir honey into vinegar mixture. Add radicchio; toss. Divide radicchio between 2 plates; top evenly with pepper, salt, nuts, and basil.