There is no such recording. A reporter who interviewed an aide of Nixon for his autobiography claimed that that aide said that (but he only claimed so after the aide had died).
I don't know about blacks or hippies, but Last Week Tonight played an Oval Office tape of Nixon wanting to target marijuana laws because those in favor (of legalization) were Jewish.
There is indeed no such recording - but calling the official an "aide" is a bit inaccurate, the official in question was the domestic policy chief[1] - rather than a random secretary that claims to have overheard something.
That all said, for all of the negative PR Nixon has received over the years he was a rather progressive and surprisingly egalitarian executive who has been praised by Indian Country Today[2] and appears to have stuck pretty close to his quaker upbringings. I think a lot of people conflate Nixon and Regan - which is pretty ridiculous when you look at the policies those two presidents actually pursued during their terms... And even more folks are getting second hand vibes from Nixon's infamous presidential debate[3] which pitted a rather uncharismatic man against JFK and led to a pretty obvious outcome.
3. https://www.youtube.com/watch?v=-9cdRpE4KKc Just FYI - if you've never seen this I'd suggest giving it a go sometime. Given recent politics it's almost fantastical to listen to two folks come into a debate focused on the issues and minimizing the ways they attacked each other.
I think the important bit is that the chief/aide/whatever didn't claim to have overheard anything at all, rather someone who talked to them claimed that they said Nixon had said that.
Hard to laud Nixon in my view, he was pretty clearly a racist man and was the originator of the "welfare queen" rhetoric (and the corresponding cuts in SNAP, etc.).
Boomers hated Nixon because he undermined the Vietnam peace process for personal political gain elongating the war that they then had to go to the trouble of dodging the draft (as long as they were rich enough).
We can be as cynical as we like about boomers and then going on to be Reagan voters, it doesn't change Nixon and Kissenger's status as unprosecuted war criminals.
I'm not overly familiar with Quaker orthodoxy, I'd be surprised if dropping bombs killing 500k Cambodians is consistent with it. Nixon wasn't all bad because no human is, even he who must not be named was kind to (some) children, we're told.