「」？
'Five minutes' counts as a noun phrase, right?
Literal
'five minutes' [topic-って] noun-phrase [with-で] good [explanatory-んですよね]?
A metalinguistic question about English grammar classification, asked in Japanese. 名詞句 'noun phrase' is a linguistic term. でいい 'is fine as, counts as' — で marks the category, いい confirms it. んですよね seeks confirmation with an explanatory-emphatic tone.