TL;DR: Officially, he is not MODOK, and they can't say if he's based on him or not.
There are definitely a few similarities which can't be totally ignored.
First, at this point, they're really just disembodied heads with robot bodies.
While Ivanov does not have a creepy spider-like body like his possible namesake, he does utilize robot bodies.
Next is their names.
Antony Ivanov is also known as The Superior, a likely reference to one of the versions of MODOK known as MODOK Superior.
Last is the almost direct shoutout.
Ivanov mentions in The Return (S04E21)
Destroy this body, sure. It was designed only for killing. My head, which you severed, is controlling many of these machines now.
While the letters behind the acronym "MODOK" change from time to time, one of the versions is Mechanized Organism Designed Only For Killing.
That said, Entertaiment Weekly specifically asked the producers/writers about this.
Anton’s head is in a glass case. Has Anton become MODOK?
WHEDON: Well, no, we can’t really say what he is. He’s definitely his own creature, but we can’t comment really as to if he’s based on a Marvel character or not.
If I were to ask if his head goes in a particular part of his new synthetic body, what would you guys say?
WHEDON: We would say no. He’s remote controlling the body with a head because Aida wants to make sure that his humanness remains intact.