Literal translation:
* Nígeríà jẹ́ orílẹ̀-èdè tó lẹ́wà. (Nígeríà jé orílẹ̀-èdè tó lẹ́wà.) This is the most direct translation. It uses the word "lẹ́wà" for "beautiful" and "orílẹ̀-èdè" for "country."
More idiomatic:
* Nígeríà lẹ́wà gan-an. (Nígeríà lẹ́wà gan-an.) This translates to "Nigeria is very beautiful." The addition of "gan-an" emphasizes the beauty.
* Nígeríà jẹ́ orílẹ̀-èdè tó ní ìwọ̀n ìlẹ̀wà. (Nígeríà jé orílẹ̀-èdè tó ní ìwọ̀n ìlẹ̀wà.) This translates to "Nigeria is a country with a lot of beauty." This is a more nuanced way to express admiration for the country's beauty.
Important Note: Yoruba has tone, which means the pronunciation of a word depends on the pitch of your voice. You can find online resources that can help you learn how to pronounce these phrases correctly.