Yes, it’s the equivalent to the Nobel in that it’s yearly with a big monetary prize, but the most prestigious award in the field remains the Fields medal, which is only awarded every four years.
The Nobel prize is usually awarded to old (around 60) researchers at the end of their career whereas the Fields medal is only awarded to researchers under 40 (and since it's only awarded every 4 years, the cutoff age can even be 36 if you're not lucky). In that sense the Abel prize is more of a Nobel equivalent than the Fields medal.
The age limit of 40 kind of ruins the Fields medal as the top prize tho. Sure, getting it is absolutely huge, but what about the people whose work's value is apparent only after decades?
