Rokko ( very tasty sweet in Turkey )
By nice, do you mean long? Very long list, if you want official list, go to a dictionary. A long word that start with an r would be, Reindeer.
Reliable, resourceful, respectful and responsible are nice descriptive words. They begin with the letter r.
Starting with what? Also, depends on what you call nice.
Radiant is very nice. It begins with the letter r.
Kindhearted is a nice word. Knowledgeable is a nice word.
Right
LustreLoveLikeLimitlessLovelyLadyLimelightLusciousLucky
Raven
immortal
· kangaroo
Retard is a negative word starting with "r".
Quintessential Quidnunc