Nasa tabi ng bintana ang paso, at nasa loob nito ang halaman.

Nasa is a very common Filipino location word. In sentences like this, it means is/are in, at, on, beside, depending on what follows.

So:

• Nasa tabi ng bintana = is beside the window
• Nasa loob nito = is inside it

A useful way to think of the pattern is:

• Nasa + place/location phrase + ang + thing

For example:

• Nasa mesa ang libro. = The book is on the table.
• Nasa kusina ang nanay. = Mother is in the kitchen.

Filipino does not need a separate word like English is in this kind of sentence.

In Filipino, sentences about location often do not use a separate verb equivalent to English to be.

Instead, the location expression itself does the job:

• Nasa tabi ng bintana ang paso.
• literally: At/beside the window the pot
• natural English: The pot is beside the window.

So this sentence is perfectly normal Filipino. English requires is, but Filipino often does not in this structure.

Filipino often places the location first and the thing being talked about after it.

So instead of:

• The pot is beside the window

Filipino commonly says:

• Nasa tabi ng bintana ang paso
• literally: Beside the window is the pot

This is a very common pattern. The part marked by ang often comes later in the sentence.

Ang is a very important marker in Filipino. It marks the topic/focus noun of the clause.

In this sentence:

• ang paso = the pot
• ang halaman = the plant

A beginner-friendly way to understand it is that ang often marks the main noun that the sentence is talking about.

So in the first clause:

• Nasa tabi ng bintana ang paso
• the thing being located is ang paso

In the second clause:

• nasa loob nito ang halaman
• the thing being located is ang halaman

Here, ng links tabi to bintana.

• tabi = side / nearby place / beside
• tabi ng bintana = the side of the window, or more naturally, beside the window

So ng here is not best translated word-for-word as a single English word every time. It often shows a relationship like of.

Compare:

• loob ng bahay = inside of the house / inside the house
• harap ng tindahan = front of the store / in front of the store
• tabi ng bintana = side of the window / beside the window

Tabi literally relates to side or next to. In actual use, it often means beside or next to.

So:

• sa tabi ng bintana = beside the window / next to the window

You will see this pattern a lot:

• sa tabi ng pinto = beside the door
• sa tabi ng kama = beside the bed

Nito means of this / of it / its, depending on context.

In nasa loob nito:

• loob = inside/interior
• nito = of it / its

So literally:

• nasa loob nito = is in its inside

Natural English:

• is inside it

Here, nito refers back to ang paso.

So the idea is:

• the pot is beside the window,
• and the plant is inside it.

This is a very common learner question.

Both nito and niya can mean something like of it / his / her / its, but they are used differently.

In this sentence, nito is used because it refers to a non-person, near or just-mentioned thing, here the pot.

Very roughly:

• nito = of this / of it
• niya = his / her / its

For objects just mentioned in a neutral descriptive sentence, nito is very natural.

So:

• nasa loob nito ang halaman = the plant is inside it

Loob means inside or interior.

It often appears in phrases like:

• sa loob = inside
• sa loob ng bahay = inside the house
• sa loob nito = inside it

So nasa loob nito is built from a very common location expression.

You can compare it with other location nouns:

• itaas = top / upper part
• ibaba = bottom / lower part
• harap = front
• likod = back
• tabi = side / beside
• loob = inside

At means and.

It connects the two clauses:

• Nasa tabi ng bintana ang paso
• at
• nasa loob nito ang halaman

So it joins two related statements into one sentence.

Yes. Filipino often allows more than one natural wording.

For example, the second part could also be expressed with a different structure, depending on style and emphasis. But the original sentence is clear and natural.

The pattern in your sentence is especially useful because it is very regular:

• Nasa + location + ang + thing

That makes it a great model sentence for learners.

Halaman usually means plant in general.

In this sentence:

• paso = pot
• halaman = plant

Together, the meaning clearly suggests a potted plant, but grammatically they are still two separate nouns:

• the pot
• the plant inside it

So Filipino is describing the setup explicitly, rather than using one single word meaning potted plant.

Yes, absolutely. It is a very good model.

You can build many sentences with this pattern:

• Nasa + place/location + ang + noun

Examples:

• Nasa mesa ang baso. = The glass is on the table.
• Nasa ilalim ng kama ang sapatos. = The shoes are under the bed.
• Nasa loob ng bag ang susi. = The key is inside the bag.
• Nasa tabi ng pinto ang payong. = The umbrella is beside the door.

This is one of the most useful everyday sentence patterns in Filipino.