Well, first of all I would suggest you to taste a good Belgian beer, certainly the best beers in the world, an added-value that few airports have on offer. I'm not suggesting you to be drunk to start your NBO flight, I'm just making you aware of an opportunity not to miss !
Appart from that, I would say that you should be able to spend a couple of relaxing hours in BRU
, as it is a rather "oversized-empty-looking" airport (even if morning hours are usualy a bit buzier), so it's in my view a pro in favour of a thransfer through BRU
when compared to competing airports.
Transfer should also be very easy as you'll stay in Terminal-B (I understand you'll be flying from the US).
For the rest, enjoy your SNBA flight to NBO !