What is N件事? (Cantonese)
It means 'numerous/several facts about Fuku Noodle'.

The slang N has an algebraic etymology which denotes an unspecified but large number (e.g., 1, 2, 3, ..., N). Apparently this emerged in the early eighties (see more here).
件 is the counter for 事 ('a thing; a matter', here its meaning is fairly abstract and dummy-like, meaning whatever that is about Fuku noodle). In fact it is common to add
counters after N: N樣嘢 ('many things'), N次 ('many times'),
N年前 ('many years ago') etc.
Of course, we don't expect countlessly many facts in a short video. Using N is often exaggeration.