Q. On Chol Hamoed does one have to eat a seuda (Yom Tov meal) or two every day, eating matza too?
A. Mishna Berura (529: 16) quotes Rambam that one is obliged on the mitzva of simcha during Chol Hamoed as he is during Yom Tov. However in regard to kavod and oneg, honoring and experiencing pleasure there is no obligatory mitzva.
Mishna Berura (530: 1) rules that although there is no compulsion to eat a seuda with bread or matza, there is a mitzva to do so at day and at night.
See Aruch Hashulchan (249: 7) Chut Shoni (7: 1) and Shemiras Shabbos K’ (42: n. 103) regarding a Chol Hamoed seuda on Erev Shabbos.
Shulchan Aruch (O.H. 188: 7) and Mishna Berura (ibid. 27) rule that since there is no compulsory mitzva to eat a seuda on Chol Hamoed, one does not have to repeat Birchas Hamazon if one forgot to recite yaale veyavo.
Rabbi A. Bartfeld