Did Nacho change the pills? And if not, would the doctors even think to check if the pills are what they say on the box?
I don't know.
I take it that Jimmy does feel a measure of empathy and regret for what he did, not just because it wasn't the way he wanted it to happen for himself. If nothing else, it feels like it'd take an incredible amount of integrity to give up a million dollars because you don't feel you personally did a job right.
I feel it's more that the characters these particular showrunners write go through a series of micro arcs rather than one big arc from A to B. By the end of BB, we could conclude that Walter White was firmly a monster (and even then, there are debates about how pure he was in that regard), but over the course of the show he'd just constantly swing back and forth. Here he is doing something for his family, here he is escalating things needlessly, here he is being selfless, here he is being selfish.
I think it's something like that. This arc had Jimmy come closer to Saul than any other previously, but it ended with his most unselfish act thus far. And it will go on like that. From here, something will prompt him to act selfishly again, then decently, then selfishly again and so on until we end up at Saul Goodman.
And I feel like that's something that would be a detriment to most other shows. But here, it just makes it feel real. All these random real life events that pull the characters this way and that, changing people but not really changing, conflating motivations, etc. It makes it really compelling.