Peel shrimp, and devein, if desired; set aside.
Bring nectar to a boil in a medium saucepan; boil 45 minutes or until reduced to 1 cup. Stir in 2 tablespoons lime juice and next 3 ingredients. Remove from heat, and cool.
Pour half of nectar mixture in a large shallow dish or heavy-duty zip-top plastic bag; add shrimp. Cover or seal, and chill 1 hour.
Remove shrimp from marinade, discarding marinade.
Grill, in 2 batches, in a grill basket over medium-high heat (350° to 400°) 3 to 4 minutes or until shrimp turn pink.
Add remaining 2 tablespoons lime juice, tomato, and next 4 ingredients to remaining nectar mixture. Cook over medium heat until thoroughly heated. Stir in shrimp; serve over rice. Garnish, if desired.
*1 pineapple, chopped, may be substituted for papaya.
NOTE: Select unblemished papayes or mangoes that yield slightly to pressure. If underripe, place in a paper bag at room temperature to speed up the process.