Learn Italian: Per i turisti, queste restrizioni sono sempre più una seccatura. - For tourists, these restrictions are increasingly a nuisance.

You would say Che seccatura!. Notice that unlike in English ("What a nuisance!"), Italian emphatic exclamations drop the indefinite article completely. You simply use Che directly followed by the noun.

Why is "increasingly" translated as sempre più instead of a single adverb?

While Italian does have a direct equivalent for increasingly (crescentemente), it sounds very formal and technical. In everyday spoken and written Italian, it is much more natural to use sempre più (literally "always more") before a noun or adjective to mean "increasingly."

Could I use sempre di più in this sentence instead of sempre più?

It wouldn't sound right here. Sempre più is used as a modifier placed directly before a noun or adjective phrase (like una seccatura). Sempre di più is usually placed after a verb to show that an action is increasing (e.g., I turisti si arrabbiano sempre di più - "The tourists are getting more and more angry").

Where does the word seccatura (nuisance) come from?