college level vs tier

college level and tier both are nouns.

Word	Noun	Adjective	Verb	Adverb
college level	Yes	No	No	No
tier	Yes	No	No	No

As nouns, tier is a hypernym of college level; that is, tier is a word with a broader meaning than college level:

college level: the level of education that college students are assumed to have attained
tier: a relative position or degree of value in a graded group

Other hypernyms of college level include grade, level.

college level (noun)	tier (noun)
the level of education that college students are assumed to have attained	one of two or more layers one atop another
	any one of two or more competitors who tie one another
	a relative position or degree of value in a graded group
	something that is used for tying
	a worker who ties something