On January 19, 1929, the flag of Nova Scotia received a royal warrant from King George V, making it the first flag in the Commonwealth approved by royal charter.
While I'm never a fan of coats of arms on flags — displaying the coat of arms is what, well, the coat of arms is for — this is actually pretty solid. The background is a Scottish flag with swapped colors, which makes sense given the province literally being called "New Scotland", and the royal arms use a small set of colors that go well with the rest of the flag.