Moj stan je najbliži stanici.

Because moj has to agree with stan.

• stan is a masculine singular noun
• here it is in the nominative because it is the subject of the sentence

So you get moj stan = my apartment.

Compare:

• moja kuća = my house
• moje selo = my village

Najbliži means closest or nearest.

It is the superlative form:

• blizak = close
• bliži = closer
• najbliži = closest

The prefix naj- is what makes the superlative in Serbian.

Here, najbliži is an adjective describing stan, so it must agree with stan in gender, number, and case.

Since stan is masculine singular nominative, the adjective is also najbliži.

A form like najbliže is an adverbial form and appears in other kinds of constructions, but in this sentence the speaker is using the agreeing adjective pattern.

Stanici is dative singular of stanica.

The basic noun is:

• stanica = station

And here the form is:

• stanici = to the station / station (dative)

With blizak / bliži / najbliži, Serbian normally uses the dative.

Because the adjective blizak and its comparative/superlative forms often take the dative to express the idea of close to something.

So:

• blizak školi = close to the school
• bliži centru = closer to the center
• najbliži stanici = closest to the station

This is just the pattern that this adjective uses.

Because Serbian often uses case endings where English uses a preposition.

In English, you say close to the station.
In Serbian, the dative ending in stanici already shows that relationship, so no extra word for to is needed here.

Serbian does not have articles like a and the.

So stanica / stanici can mean a station or the station, depending on context.

In this sentence, it will usually be understood as the station, because both speaker and listener normally know which station is meant.

Yes, and that is a very common sentence.

But the meaning is slightly different:

• Moj stan je blizu stanice = My apartment is near the station
• Moj stan je najbliži stanici = My apartment is the closest to the station

So blizu just says near, while najbliži adds a comparison.

Yes. Serbian word order is more flexible than English word order.

The neutral version is:

• Moj stan je najbliži stanici.

But for emphasis, you could also say:

• Najbliži stanici je moj stan.

That puts more focus on closest to the station.
Still, not every possible rearrangement sounds equally natural, so the original sentence is the safest standard order.

Yes, in a normal present-tense sentence like this, je is needed.

It is the 3rd person singular of biti = to be:

• je = is

So:

• Moj stan je najbliži stanici. = My apartment is closest to the station.

In standard Serbian, you would not normally leave je out in this kind of sentence.

Both are fine translations.

• stan = apartment / flat
• kuća = house

So a British English speaker may naturally think flat, while an American English speaker may naturally think apartment.