Wednesday Night: Chicken, Snow Peas, and Pasta in Cream Sauce

This was one of my standard, midweek "too lazy to go shopping, let's clear stuff out of the fridge/freezer" meals. It turned out quite well, though I wouldn't have been sad to have a bit more acidity (white wine?) in the sauce.

1 chicken breast and 2 chicken thighs, cut into small pieces
1/2 red onion, small dice
3 scallions, thinly sliced
4 oz. snow peas, cut in half
4 cloves garlic, minced (I used sherry-pickled garlic)
olive oil
2 Tbs butter
1 Tbs flour
1 cup milk
2 Tbs sour cream
some sherry (2 Tbs? 1/4 cup? something like that)
salt, pepper, cayenne, nutmeg
spaghetti

Brown the chicken pieces well in olive oil and set them aside in a bowl. (I should have salted and peppered the chicken first, but I forgot).
While the chicken is browning, melt the butter in separate pan over medium heat until it stops foaming. Whisk in the flour and cook until lightly browned. Reduce the heat to low and whisk in the milk in small batches. Whisk in the sour cream and sherry. Add whatever liquid collected under the chicken and enough pasta water to get the sauce to the consistency you want. Hold this over low heat, stirring occasionally, until everything else is done. Adjust seasonings with salt, pepper and cayenne.
Cook the onion and scallions in the same pan until they're soft. Toss in the snow peas and stir for 30 seconds or so, just until their color darkens.
Throw the chicken and onion mixture into the sauce, grind in a bit of nutmeg. Stir to incorporate.
Serve over spaghetti.