BRING broth to boil in small saucepan on medium-high heat; remove from heat. Stir in couscous; cover. Let stand 5 min.
MEANWHILE, cook and stir eggplant, green onions and garlic in hot oil in large skillet on medium-high heat 5 to 7 min. or until tender. Stir in couscous along with the tomato and basil. Reduce heat to low; cook 1 to 2 min. or until heated through, stirring occasionally.
STIR in walnuts.