Ako ništa drugo, natjecanje je zabavno.

Yes, ako normally means if, but Ako ništa drugo is a fixed idiomatic expression meaning if nothing else, at least, or if for no other reason.

So in this sentence, it introduces a kind of fallback point:

• Ako ništa drugo, natjecanje je zabavno.
• If nothing else, the competition is fun.

It does not mean a real condition in the usual if X, then Y sense. It is more of a discourse phrase.

Because Ako ništa drugo functions like an introductory phrase or comment on the whole sentence, so it is naturally set off with a comma.

It works similarly to English phrases like:

• At least, ...
• After all, ...
• In any case, ...

So the comma helps show that Ako ništa drugo is not the main clause itself, but a framing expression for what follows.

Here ništa drugo is in the nominative/accusative neuter singular form, which is the form you normally see with ništa.

• ništa = nothing
• drugo = other, agreeing with ništa

In this idiom, you do not need to over-analyze it as a full literal structure. Learners should mainly recognize Ako ništa drugo as a set phrase meaning if nothing else.

Because drugo agrees with ništa, which is grammatically treated as neuter singular.

So:

• drugi = masculine
• druga = feminine
• drugo = neuter

Since ništa takes neuter agreement, the adjective also appears in the neuter form:

• ništa drugo = nothing else

Natjecanje means competition, contest, or sometimes tournament/event of competing, depending on context.

It is a broad word and can refer to:

• a sports competition
• a school contest
• a talent competition
• any organized competitive event

So it is wider than a single English word like race or match.

Because nouns ending in -nje are very often neuter in Croatian.

So:

• natjecanje = neuter
• singular nominative: natjecanje
• that is why the adjective later is also neuter: zabavno

This is a useful pattern to remember: many verbal nouns in -nje are neuter.

Because zabavno is an adjective agreeing with natjecanje, which is neuter singular.

Compare:

• film je zabavan = the film is fun/entertaining (film is masculine)
• igra je zabavna = the game is fun (igra is feminine)
• natjecanje je zabavno = the competition is fun (natjecanje is neuter)

So the adjective changes to match the gender and number of the noun.

Je is the 3rd person singular present of biti (to be), but in Croatian it is also a clitic, which means it tends to go in second position in its clause.

In the main clause here, the subject is natjecanje, and the clitic comes right after it:

• natjecanje je zabavno

That is the normal order.

The introductory phrase Ako ništa drugo stands outside the main clause, so it does not force je to come immediately after ako.

Yes, that is possible, but the nuance changes slightly.

• Ako ništa drugo, natjecanje je zabavno.
  = starts with the fallback idea: if nothing else...

• Natjecanje je zabavno, ako ništa drugo.
  = puts the main statement first, then adds if nothing else almost as an afterthought.

Both are understandable, but the original version sounds more natural when you want to frame the whole statement that way from the start.

Usually fun is the most natural translation here.

But zabavan / zabavna / zabavno can also mean:

• entertaining
• amusing
• enjoyable

So the exact English word depends on context. In this sentence, fun is probably the best fit:

• The competition is fun.

Because Croatian does not have articles like English a/an/the.

So natjecanje can mean:

• a competition
• the competition
• competition

The exact meaning depends on context. English has to choose an article, but Croatian does not mark that distinction directly.

It is quite neutral and natural. The phrase Ako ništa drugo is common in both speech and writing.

The sentence does not sound especially formal or especially slangy. You could hear or read it in many contexts:

• conversation
• commentary
• journalism
• essays

So it is a very useful phrase pattern to learn.

Yes, very often. It is a productive phrase.

For example:

• Ako ništa drugo, nešto smo naučili.
  If nothing else, we learned something.

• Ako ništa drugo, bilo je zanimljivo.
  If nothing else, it was interesting.

• Ako ništa drugo, pokušali smo.
  If nothing else, we tried.

So once you learn it as a chunk, you can reuse it easily.