Learn Turkish: Bu kitap elbette güzel. - This book is certainly nice.

In Turkish, you often don't need a specific word for "is" in simple present tense sentences. The word güzel is an adjective meaning "nice", but acting as the main point at the end of the sentence automatically makes it mean "is nice".

I thought güzel meant "beautiful". Why is it translated as "nice" here?

You are right that güzel translates to "beautiful" when talking about people or scenery. However, Turkish uses it much more broadly than English does. When talking about things like books, movies, ideas, or food, güzel simply means "good" or "nice".

Why is elbette placed in the middle of the sentence?

Words like elbette (certainly / of course) usually go right before the word they emphasize. Here, it emphasizes güzel, so it comes directly before it to mean "certainly nice". You could also put it at the very beginning of the sentence to emphasize the whole thought.

Could I use tabii ki instead of elbette here?

Yes! Tabii ki (of course) has a very similar meaning and is used in the exact same way. Elbette just sounds slightly stronger and more definitive, like saying "certainly" or "absolutely" instead of "of course".