Poetry is most certainly a form of a literature.[1]

And Bob Dylan is widely considered to be a poet. Ginsberg considered him a poet. The lyrics for "Mr. Tambourine Man” are in the 10th edition of The Norton Introduction to Literature. The lyrics to "Desolation Row” are in 2006 Oxford Book of American Poetry. Dartmouth teaches a class that analyzes the poetry of Dylan.[2]

It was also not the first time the Nobel for Literature was awarded to a poet. Poet Erik Axel Karlfeldt was awarded the Nobel for Literature in 1931.[3]

[1] https://en.wikipedia.org/wiki/Outline_of_literature

[2] https://www.dartmouth.edu/~dartlife/archives/16-4/renza.html

[3] https://www.nobelprize.org/prizes/literature/1931/karlfeldt/...