https://www.youtube.com/watch?v=9EzPkqJqp9MEach member of Congress has to decide how much staff they hire and what sort of remuneration (if any) said staff will be paid.
Breaking with the usual practice, Rep. Ocasio-Cortez decided that her entry-level staff would all be paid a living wage--around $52,000 (DC-area costs of living being higher than many other places). However, due to budget constraints, this means that she can only afford to pay her chief of staff, Saikat Chakrabarti, around $80,000.
The general going salary for a chief of staff for a member of the House is around $150,000.
One assumes that, if Mr. Chakrabarti were miffed about being paid half as much as his counterparts, he would quit. Last I heard, he hasn't.
I should note that Mr. Chakrabarti worked on Sen. Sanders' 2015-16 Presidential campaign, and later helped co-found and run Justice Democrats, the group that discovered and recruited Ms. Ocasio-Cortez, for free.
To my knowledge, no actual laws are being broken here.
And FOX News thinks it's an outrage that Mr. Chakrabarti is willing to work as a Congressional chief of staff for $80,000 and that entry-level staff would get $52,000--"socialism and communism" according to one host.
How about capitalism: Rep. Ocasio-Cortez and Mr. Chakrabarti have agreed upon a salary each considers fair for him to receive as her chief of staff (I imagine this is not the only position available to him), and meanwhile she can offer prospective entry-level staffers a substantially higher salary than they would get with pretty much anyone else in Congress, thus likely providing her a much more talented, motivated staff than anyone else in Congress.
I have to wonder if they secretly think she'd be easy to beat in a higher-level campaign (though I doubt she'd lose in New York if she ran for Senate, but then it'd take a lot for any Democrat to lose in New York these days--Anthony Weiner probably could've--so probably President) and are making stupid attacks against her on purpose to prop her up.