Non che il prezzo sia alto, ma il soprammobile è sbeccato.

Here Non che means something like It’s not that... or Not that....

So the sentence is setting up a contrast:

• Non che il prezzo sia alto = It’s not that the price is high
• ma il soprammobile è sbeccato = but the ornament is chipped

The speaker is saying: the problem is not the price; the real issue is that the object is damaged.

This structure is common when someone wants to reject one possible explanation and introduce the real one.

Because sia is the present subjunctive of essere, and after this kind of expression Italian normally uses the subjunctive.

• è = indicative
• sia = subjunctive

In Non che il prezzo sia alto, the speaker is not simply stating a fact. They are presenting an idea and dismissing it as the main issue. That kind of nuance often triggers the subjunctive in Italian.

So:

• Non che il prezzo sia alto = correct
• Non che il prezzo è alto = not standard in this use

Yes, you can think of it as related to fuller expressions like:

• Non è che il prezzo sia alto...
• Non è che il problema sia il prezzo...

In everyday Italian, Non che... can work as a more compact way of saying It’s not that...

So the sentence has a slightly elliptical feel, but it is perfectly natural.

Literally, alto means high, but with prezzo it corresponds to high/expensive in English.

So:

• un prezzo alto = a high price
• naturally in English: an expensive price is less idiomatic; we usually say the price is high or simply it’s expensive

In this sentence, il prezzo sia alto means the price is high.

A soprammobile is a decorative object you place on furniture, shelves, or tables.

Possible English equivalents include:

• ornament
• decorative object
• knick-knack
• figurine (in some contexts)

It is not really the furniture itself; it is something placed on top of furniture as decoration.

Sbeccato means chipped, especially when a hard object has a small piece broken off at the edge.

For example, it can describe:

• a cup with a chipped rim
• a plate with a chipped edge
• a ceramic ornament with a small broken corner

So il soprammobile è sbeccato means the ornament is chipped.

Because sbeccato agrees with il soprammobile, which is:

• masculine
• singular

So the adjective/past-participle form is:

• sbeccato = masculine singular

Compare:

• il soprammobile è sbeccato
• la tazza è sbeccata
• i piatti sono sbeccati
• le tazze sono sbeccate

Agreement is very important in Italian.

Ma means but, and it introduces the real complaint after rejecting another possible complaint.

So the logic is:

• Not that the price is high
• but rather, the object is chipped

It creates a contrast between:

1. a possible issue that is being dismissed
2. the actual issue the speaker cares about

A few natural translations are:

• It’s not that the price is high, but the ornament is chipped.
• It’s not the price that’s the problem; the ornament is chipped.
• It’s not that it costs too much; the ornament is chipped.

The best version depends on tone, but the core meaning is: the price is not the issue; the damage is.

Yes, a little. Non che... can sound slightly more polished or compressed than very basic spoken Italian.

In everyday speech, many speakers might also say something like:

• Non è che il prezzo sia alto, ma il soprammobile è sbeccato.
• Il prezzo non è alto, però il soprammobile è sbeccato.

Your sentence is perfectly good Italian, but learners should know that there are more conversational alternatives too.

No. They are different.

• non che = two separate words, as in this sentence, meaning not that
• nonché = one word, meaning something like as well as, and also, or in some contexts a formal linking expression

So in your sentence, it must be Non che, not nonché.

Yes. This is a useful pattern.

Examples:

• Non che il film sia brutto, ma è troppo lungo.
  It’s not that the movie is bad, but it’s too long.

• Non che Maria sia antipatica, ma è molto fredda.
  It’s not that Maria is unpleasant, but she’s very cold/distant.

• Non che il ristorante sia caro, ma il servizio è lento.
  It’s not that the restaurant is expensive, but the service is slow.

The general pattern is:

Non che + noun/pronoun + subjunctive, ma...

That makes it a very useful structure for nuance and polite criticism.