Learn Portuguese (Portugal): Há tanto caos na rua que é difícil circular. - There is so much chaos in the street that it is difficult to circulate.

In Portuguese, you use tanto (and its variations) before nouns to mean "so much" or "so many". Here, caos (chaos) is a masculine singular noun, so we use the masculine singular tanto. You only use tão before adjectives and adverbs (like saying "so big" or "so fast").

Does the verb circular literally mean going in circles here?

No, in this context, circular means to move around, flow, or navigate. It is very commonly used in Portuguese to talk about traffic moving on a road or people getting through a crowded area, so here it translates best as "to get around".

Why doesn't é difícil include a word for "it"?

Portuguese doesn't use dummy subject pronouns like "it" for impersonal statements. Where English says "it is difficult", Portuguese simply says é difícil (literally "is difficult").

I see Há for "There is". Do European Portuguese speakers ever use Tem instead?

In European Portuguese, Há (from the verb haver) is the standard and correct way to say "there is" or "there are". While you might occasionally hear ter used this way in very informal slang, haver is the rule in Portugal, unlike in Brazil where Tem is standard.