Also have this issue, seems to have to do with the PATH variable set in /data/data/com.offsec.nhterm/files/usr/bin/kali, at one point I had it mostly fixed by editing the file manually (this was on 2025.2 on A13, but needed to upgrade for other reasons). It seems to also happen on 2025.2 on A15; potentially it has to do with changes in newer Android I'm not sure if it also happens on older versions.

EDIT: Reproduced the workaround, add /product/bin (or whatever directory which su gives you in an emergency shell) to the first export PATH= statement and it will work again

adb shell
su

Find su binary:

ls -l /product/bin/su /system/bin/su /system/xbin/su /sbin/su 2>/dev/null
lrwxrwxrwx 1 root root 8 1970-01-11 22:58 /product/bin/su ->

(backup) "/data/data/com.offsec.nhterm/files/usr/bin/kali"

(edit) "/data/data/com.offsec.nhterm/files/usr/bin/kali"

Add "/PATH_TO_YOUR_SU:/system/bin:" to export PATH=/data/data/com.offsec.nhterm/files/home/.nhterm/script:/data/data/com.offsec.nhterm/files/usr/bin:/data/data/com.offsec.nhterm/files/usr/sbin:/sbin:/bin

Complete:
export PATH=/product/bin:/system/bin:/data/data/com.offsec.nhterm/files/home/.nhterm/script:/data/data/com.offsec.nhterm/files/usr/bin:/data/data/com.offsec.nhterm/files/usr/sbin:/sbin:/bin

Reload nhterm