In the sentence:
でも今は問題なく食べることができます
Demo ima wa mondai naku taberu koto ga dekimasu"
what is the grammatical nature of "mondai naku"? Is it a noun, an adjective or an adverb?
In the sentence:
でも今は問題なく食べることができます
Demo ima wa mondai naku taberu koto ga dekimasu"
what is the grammatical nature of "mondai naku"? Is it a noun, an adjective or an adverb?
It's adverbial, i.e., it modifies a verb. In general, the ku-form of an adjective is also known as the adverbial form.
ない is a bit special in that it can take certain nouns and work like a suffix meaning "-less(ly)", but the resulting phrase is still grammatically an adjective, so its ku-form is adverbial. You can think 問題ない is a distinct adjective.
Similar example:
One note is that I feel that なく in cases like this can simply be a shorter and more formal form of なくて if that helps...
So your sentence can also be written as "でも今は問題(が)なくて、食べることができます".