Did a second try at the chicken tinga tacos I originally tried in February, making the change I most wanted (ditching the canned chipotle in adobo sauce) and getting pretty good results.
I boiled half or so an onion, two cloves of garlic, and 20oz of boneless chicken breast with 3 chopped chipotle peppers (these were actually labeled “Morita”; in any case, smoked red jalapeño), for a bit over an hour. Just enough water to cover by the end (I didn’t have to top it up). Drain, reserving liquid. Don’t bother trying to separate the chicken from the rest if you started from boneless like this. Some rough stirring towards the end will break up the bits nicely, too. Still, full breasts or a full chicken would probably be better, I will try that when I’m ready for a big batch.
Then I sautéed another onion and a bit and 3 cloves of garlic in some olive oil, and added 1/2tsp ground coriander and 1/2tsp whole cumin seed. When this was well started, I added a small can of tomato sauce. This was probably too much, or the wrong thing; 1/2 cup of minced tomato would probably have been better, or sauce rather than paste, or less. Too much sweetness came through to the end, and I think it was from the paste.
When the tomato paste was well mixed in I added the meat and mixed it around a lot. I started adding the reserved liquid back fairly early, to get the texture “right”.  In the end I used about 3/4 of the reserved liquid.
Serve in small white corn tortillas, with minced onion. (And coriander leaf if you like that, which I don’t all that much, and didn’t have any on hand.)
The result was good. I’d have liked more spice and a bit more front-of-mouth spice, probably some cayenne in with the spices would have been good. And probably a 4th chipotle into the boiling stage. The smokiness came through decently, and another chipotle plus the cayenne should give about the right heat. Definitely less tomato paste, or some other form of tomato.
Two dinners plus 4 units of leftovers again.
I think after one more decent batch, I’ll be ready to do a big batch and have lots of leftovers.