Here Noodles, I'll be "that guy", only because you need to know what to look for if there is going to be an issue...
No, he's not going to become impacted from 2 tiny pieces of shell, he'd have to eat a good amount to become impacted...That being said, they cannot digest the shells of an Almond (although they can digest some seed shells), but again, he'd have to eat quite a bit of shell to become impacted. It will most-likely pass in his droppings without you even knowing about it.
****The usual complications that happen when a parrot eats a nut shell are #1) Crop blockage/becoming lodged in the Crop due to the sharp edges of the shell pieces, and #2) GI bleeding due to the shell pieces either cutting the GI Tract, OR becoming lodged in the lining of the GI Tract due to the sharp edges.
The only time I myself have ever seen a complication from a bird eating shell pieces was a blockage in the Crop, which required an Endoscopy with a flush...We had no idea what was wrong with the bird (a Moustache Parakeet), he started trying to "regurgitate", as I was told, but when I went to check on him he was actively regurgitating over and over and over again, and he was bringing stuff up, but he kept doing it at different times throughout the day, and then into the next day, and it obviously wasn't normal regurgitating. Otherwise he seemed totally fine, he kept eating and drinking and playing, was friendly and not at all stressed. After 2 days of him just continually trying to regurgitate what I thought was way too often, I called our CAV and he stopped over to take a look at him, and agreed that something wasn't quite right...So the next day we took him into the office, they used Iso-gas to sedate him, used the Endoscope to look inside of his Crop, and did a flush where everything in the crop was flushed into a white-colored towel...Got a bunch of stuff actually, little bits of fabric, some gooey food stuff that wouldn't leave the Crop, and they had seen the piece of shell with the Endoscope and pulled it out, as it wouldn't come out with the flush and was the only thing left behind after the flush...It wasn't a large piece of shell, it was tiny, but it was sharp!!! After they took it out he was completely fine, no issues at all, and the CAV put him on an Anti-Fungal because they found a bit of yeast that came out with the flush...that was it, no big deal.
So I would try not to worry too much about a couple tiny little pieces of nut shell, but just keep an eye on him...You know what to look for, and if you see anything off then you know what to do...Obviously any blood in his droppings is a red-flag for GI bleeding, or any blood from his mouth or nostrils, or any chronic/constant, or let's say "more than typical/normal" Crop adjustment or regurgitating...And of course any typical signs of pain and/or illness, specifically a loss of appetite or complete anorexia is the big one with something like this, due to the GI pain that a piece of lodged shell would cause...
It will probably pass right out of him without any issue at all. Just keep a close eye on him, his appetite, and his droppings.
