Q. Since Purim is a special day for tefillah, is one allowed to say tehillem on Purim night? Or is tehillem not allowed to be said by an individual at night?

A. Indeed Purim is a special day for tefilos, similar to Yom Kippur (Tikunei Zohar 22) and since “whoever stretches out his hand we give to him on Purim” (Yer. Megilah 1:4) Hashem behaves in a similar way to us, if we ask properly he grants our wishes (Nidvos Pi.)
Horav Shlomo Miller’s Shlit”a opinion is that you are allowed to recite Tehilim on Purim night.

Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit”a