Reciting Nishmas Daily

 https://outorah.org/p/112761/

When I was in high school, I went to visit Rav Moshe Feinstein ztz”l and one of the questions I asked him was about reciting Hallel on a day on which Chazal did not institute it. He replied that doing so would constitute an interruption in the order of tefillah. Therefore, if one feels that a day warrants extra praise to Hashem, one may recite the paragraphs that constitute Hallel after davening, without a bracha.

 I forwarded my draft to a more senior colleague to make sure that my conclusion was correct. He referred me to a ruling from Rav Chaim Kanievsky, who said the exact same thing, i.e., that that one may not say Nishmas daily as part of pesukei d’zimra but that one may do so after davening. He also specifies that reciting it daily is without the bracha.