nl100 QQ 3brl spot?

Without analyzing too deep I'd say river is a check-fold or block-bet spot.

Let's examine our three normal options:

1. Bet. Here we're betting for value. We need to make assumptions about villain's calling range. Let's give him 44 but not 22, he might have neither and he might have both.

River calling range would be: 22,44,77,66,JJ AsQs (one combo to represent floated spades), and some number of overpairs. Since we have 16 combos of hands that beat us, we would need 3 seperate overpairs. We get this directly if villain calls 88,99,TT on river.

If this is the case you can valuebet. I think this is a pretty optimistic scenario, and in practice you are just behind villain's calling range, so you can't valuebet river.

What about checkcall? Doesn't seem like villain will have hands that bluff, so I'd say you are way behind and it's not an option.

So... checkfold or bet really small :-)

In the future to decide whether or not to bet, use equilab and estimate villain's expected river strategy, and check your equity for betting.

I would go so far as to say that even block betting is bad

Board: 2c7s4h6sJs
Equity Win Tie
MP2 58.82% 58.82% 0.00% { QhQc }
MP3 41.18% 41.18% 0.00% { JJ-44, 22, 97s, 87s, 76s, As5s, As4s, As3s }

This is hero's equity against villain's River range. I think you would need at least a 65% edge to even consider making a blocking bet.

Hey, if we took from his range 22 which might fold pre and 44 which might raise flop or turn then we have 66,6% equity against his range.
Do you givem all sets on the river, cause its good board to slowplay and wont be raised too often?

I think the board is decent to slowplay on but not great. You are right that we shouldnt probably discount those a little which could make this more of a blockbetting spot.

How would u react against a raise? Are u protecting your blockbetting range with some nut combos?

I think I would call raise with QsQx and AsAx, cause they have best blockers to nuts.
The reason for blckbt is to get called by 88/99/TT which is 18 combo. Id assume he will call half of it to blockbet (most likely with spade) which is 9 combo.
He has probably around 9 sets as well, it depends, so it looks like super close and I guess its not worth a risk with that hand.
Its better to blockbet with AsAx from overpairs, cause it removes flush from his range and he might sometimes have QQ that will call.