Combine garlic powder, cumin, paprika, ginger, allspice, salt and pepper in a large self-sealing bag. Add pork cubes; seal bag and toss until pork is evenly coated. Heat oil over medium-high heat in large nonstick skillet. Add pork cubes; cook and stir 4-5 minutes, or until nicely browned.
Meanwhile, bring broth to a boil in a medium saucepan. Stir in couscous, cover, remove from heat and let stand 5 minutes. Stir in tomatoes, onion, cilantro, parsley, and mint. Spoon couscous onto serving platter; top with pork cubes. Drizzle lemon juice over pork and couscous, garnish with cilantro.