mixed bag vs assortment

mixed bag and assortment both are nouns.

Word	Noun	Adjective	Verb	Adverb
mixed bag	Yes	No	No	No
assortment	Yes	No	No	No

As nouns, mixed bag and assortment are synonyms defined as:

mixed bag and assortment: a collection containing a variety of sorts of things

Other synonyms of mixed bag include miscellanea, miscellany, mixture, motley, potpourri, salmagundi, smorgasbord, variety.

mixed bag (noun)	assortment (noun)
a collection containing a variety of sorts of things	the act of distributing things into classes or categories of the same type
	a collection containing a variety of sorts of things