I don’t know in English but in French, the meaning of ” où nous pouvons apprendre ” and ” où on peut apprendre ” is not the same. ” on ” is informal here, ” nous” is not. In this situation if you say “nous”, it means you are talking for a precise group of persons and you include yourself. If you use “on”, it’s not someone specific, it’ s people in general
As already answered in a comment, the context is generally telling how to interpret on in a sentence. Usually on is either “one” or “we” but it might also be any other personal pronoun. depending on the sentence. Really ambiguous cases are rare.
In your example, because of the generic present, there is no doubt the meaning is “a place where ballroom dancing is taught”.
If the speaker wants to include themself in the learners, that would more likely be we using the conditional that way:
…un endroit où on pourrait apprendre des danses de salon.
Note that the pronoun nous hasn’t disappeared in spoken or informal French. What has almost completely disappeared in everyday spoken French is the first person plural verb forms (pouvons, pourrons, pourrions…)
That means nous is no more a direct subject but it can still be an affixed one like in:
…un endroit où nous, on peut apprendre des danses de salon. (here, the question implies there are places where ball dancing is taught but not for us for some reason).
Note also that nous is the only choice as a complement:
C’est nous qui apprenons les danses de salons.
This form is a rare case where the first person plural is still used in the conversation, although you might also hear or read in very relaxed informal French :
C’est nous qu’on apprend…