煮込み is read as にこみ (nikomi) and means stew.
にこみ
nikomi
にこむ
to cook (various ingredients) together
みそにこみうどん
udon cooked in a broth containing miso paste
にる
to boil
につめる
to boil down
にもの
nimono
にたつ
にえきらない
half-cooked
につまる
to approach a conclusion (of a discussion, investigation, etc.)
にじる
broth
にぼし
(small crunchy) dried sardines
にだす
to extract essence by boiling
にあい
stew made from multiple ingredients