Portionen er stor nok til os begge, så vi deler den.

Because portionen is the definite form: the portion.

In Danish, the definite article is often added to the end of the noun:

• en portion = a portion
• portionen = the portion

Since portion is a common-gender noun (it takes en), the definite ending is -en.

Danish adjectives agree with the noun in gender and number.

Here, portionen is:

• singular
• common gender

So the adjective is stor.

Compare:

• en portion er stor = a/the portion is big
• et måltid er stort = a/the meal is big
• portionerne er store = the portions are big

Because stor comes after er here, it is a predicative adjective, and that is why you do not use the definite form store.

Nok means enough.

In Danish, enough usually comes after the adjective:

• stor nok = big enough
• gammel nok = old enough
• hurtig nok = fast enough

So Danish says big enough in the order big + enough, just like English.

After nok, Danish often uses til to mean for in the sense of being sufficient for someone or something.

So:

• stor nok til os begge = big enough for both of us
• god nok til jobbet = good enough for the job
• varm nok til børnene = warm enough for the children

This is a very useful pattern:

adjective + nok + til + person/thing

Because os is the object form of the pronoun, while vi is the subject form.

Use:

• vi = we
• os = us

After a preposition like til, Danish uses the object form:

• til os = for us
• not til vi

So til os begge is correct.

Begge means both.

Without it, til os would just mean for us.
With begge, it becomes more specific: for both of us.

So:

• til os = for us
• til os begge = for both of us

It makes it clear that the portion is enough for the two people together.

Here så means so.

It connects the two clauses:

• Portionen er stor nok til os begge
• så vi deler den

So the second clause is the result or consequence of the first one:

the portion is big enough for both of us, so we share it.

Be careful: så can also mean then or so/very, depending on context, but here it is a conjunction meaning so.

Because så is joining two main clauses.

The second clause keeps normal main-clause order:

• vi deler den = we share it

So after så, you get:

• så vi deler den

This is different from some adverbs that trigger inversion. For example:

• Derfor deler vi den = Therefore, we share it

But with conjunction så, the usual order here is:

• så vi deler den

Deler is the present tense of at dele.

• at dele = to share / to divide
• deler = share / are sharing

In this sentence, it means share in the sense of splitting it between two people.

Danish present tense is often used where English also uses the simple present:

• vi deler den = we share it / we’re sharing it

Because den refers back to portionen, and portion is a common-gender noun.

In Danish:

• common gender nouns take den
• neuter nouns take det

So:

• en portion → den
• et stykke → det

Even though English just uses it, Danish has to choose between den and det based on the noun’s grammatical gender.

It can mean both in different contexts, but here it clearly means share.

Examples:

• Vi deler regningen = We split/share the bill
• Vi deler kagen = We share the cake
• De deler landet i to = They divide the country in two

So in this sentence, vi deler den means that the two people will split the portion between them.

Normally, til is the natural choice here, not for.

So:

• stor nok til os begge = natural
• stor nok for os begge = not the usual phrasing here

English often uses for, but Danish commonly uses til after nok in this kind of sentence. That is something English speakers often need to get used to.