Process basil, 1/4 cup pecans, olive oil, and next 3 ingredients in a blender or food processor until smooth, stopping to scrape down sides. Remove 1/2 cup pesto, and reserve for other uses. Toss hot green beans with remaining pesto; sprinkle with remaining 1/4 cup pecans.
NOTE: Spoon leftover pesto into a airtight container; refrigerate up to 2 weeks, or freeze up to 3 months.
