Discard tough stems from greens. Cut top 5 inches from greens and reserve. Cut remaining greens into 3/4-inch slices. Transfer all greens to a large serving bowl. Coarsely chop nuts and finely chop garlic. In a small heavy skillet cook garlic and nuts in oil over moderate heat, stirring, until garlic is golden. Stir in vinegar and salt and pepper to taste.
Pour hot vinaigrette over greens and toss to combine.