I know about the jpeg that's been floating around Twitter everywhere. I'd read she'd taken a left turn on deficits in recent years but on that detail I could be mistaken.
Again, here's an article from Neera Tanden about her opinions -
https://democracyjournal.org/magazine/a-new-social-contract-for-the-21st-century/
In which she supports a UHC system w/ a strong public option open to anyone, paid & sick leave, a National Health Service Corps, and heavy investment in renewal jobs. Yes, Neera had some shittier opinions before. Welcome to politics. Not everybody comes out of the womb with the "correct" ideas. After all, some Presidential candidates even said open borders were a Koch brothers proposal, opposed DOMA based on state's rights instead of being loud for gay rights, and voted for the '94 crime bill.
The most important thing for an OMB director after all isn't their personal beliefs, but how'd they score bills. Everything Neera has said since 2016 shows that she'd score welfare expansion bills positively. I'm no Tanden fanboy, so I don't really care who's in charge as long as they'll score things well, I just think the actual reality is a Sperling & Tanden OMB reign wouldn't be much different, especially since it's not like Sperling has been always great on economic matters either, but like Tanden, he's moved to the left over the past few years looking at the evidence.
The actual reality is Neera would be the most left-wing OMB director probably since LBJ (or more accurately, probably Nixon). Hopefully, Neera stepping down doesn't lead us to somebody being named to the position like Bruce Reed, who actually still is talking positively in 2020 about welfare reform, unlike Tanden.