Questa salsa è buona con il pollo.

Because salsa is a feminine singular noun in Italian, and the demonstrative questo/questa has to agree with it.

• questo = this, for masculine singular
• questa = this, for feminine singular

So:

• questa salsa = this sauce
• questo pollo = this chicken

Agreement is very important in Italian.

For the same reason: buona has to agree with salsa, which is feminine singular.

• buono = good, masculine singular
• buona = good, feminine singular
• buoni = good, masculine plural
• buone = good, feminine plural

Since salsa is feminine singular, you say questa salsa è buona.

The accent distinguishes è (is) from e (and).

• è = is
• e = and

So in this sentence, è buona means is good.

This accent is mandatory in standard written Italian.

Italian often uses the definite article where English may not.

So although English says with chicken, Italian naturally says con il pollo.

Here, il pollo means the chicken, but in context it often has a more general sense, like with chicken dishes or with chicken as a food.

This is very common in Italian:

• mi piace il caffè = I like coffee
• mangio la pasta = I eat pasta
• buono con il pollo = good with chicken

Yes. Col is a contraction of con il.

So these are both possible:

• Questa salsa è buona con il pollo.
• Questa salsa è buona col pollo.

They mean the same thing.
Con il may feel a little more neutral or careful in writing, while col is very common in everyday speech and writing too.

Con means with, so it expresses that the sauce goes well together with chicken.

• buona con il pollo = good with chicken

Per usually means for, so it would change the meaning:

• una salsa per il pollo = a sauce for chicken / a sauce intended for chicken

So:

• è buona con il pollo = it tastes good when eaten with chicken
• è una salsa per il pollo = it is a sauce meant for chicken

They are related, but not identical.

Yes. In food contexts, buono/buona often means:

• good
• tasty
• delicious
• nice

So Questa salsa è buona con il pollo can be understood as:

• This sauce is good with chicken.
• This sauce tastes good with chicken.

Italian often uses buono in a very natural, food-related way.

The standard order here is:

• Questa salsa = subject
• è = verb
• buona = adjective/complement
• con il pollo = prepositional phrase

So Questa salsa è buona con il pollo is the most natural neutral order.

You can sometimes move things around for emphasis, but that is less neutral. For example:

• Con il pollo, questa salsa è buona.

This sounds more marked, as if you are emphasizing with chicken specifically.

For a learner, the original word order is the safest choice.

A simple pronunciation guide:

• questa ≈ KWEH-sta
• salsa ≈ SAHL-sa
• è ≈ eh
• buona ≈ BWOH-na
• con ≈ kon
• il ≈ eel
• pollo ≈ POHL-lo

A few useful notes:

• qu in Italian is usually like kw
• buo in buona sounds like bwo
• ll in pollo is pronounced clearly as a doubled consonant, not like English y

So the whole sentence is roughly:

KWEH-sta SAHL-sa eh BWOH-na kon eel POHL-lo

In Italian, nouns have grammatical gender, and pollo is a masculine noun.

That is why it takes:

• il pollo = the chicken

If it were feminine, it would take la, but it does not.

You generally have to learn the gender together with the noun:

• il pollo
• la salsa

This helps you choose the right article and adjective forms.

Yes. That would also be correct, but the meaning changes slightly.

• Questa salsa è buona con il pollo. = This sauce is good with chicken.
• La salsa è buona con il pollo. = The sauce is good with chicken.

Questa points to a specific sauce, often one near you or one already being discussed.
La salsa just refers to the sauce more generally or to a known sauce in the conversation.