litchi vs litchi nut

litchi and litchi nut both are nouns.

Word	Noun	Adjective	Verb	Adverb
litchi	Yes	No	No	No
litchi nut	Yes	No	No	No

As nouns, litchi and litchi nut are synonyms defined as:

litchi and litchi nut: Chinese fruit having a thin brittle shell enclosing a sweet jellylike pulp and a single seed; often dried

Other synonyms of litchi include leechee, lichee, lichi, litchee, lychee.

litchi (noun)	litchi nut (noun)
Chinese fruit having a thin brittle shell enclosing a sweet jellylike pulp and a single seed; often dried	Chinese fruit having a thin brittle shell enclosing a sweet jellylike pulp and a single seed; often dried
Chinese tree cultivated especially in Philippines and India for its edible fruit; sometimes placed in genus Nephelium