Unable to install Express (of Node.js) in Android Termux using sdcard0 as directory
Unfortunately, the answer is No, not even with root.

Android uses FUSE (Filesystem in USErspace), which has symbolic links disabled. Since Node needs to setup symlinks, it's impossible to install it onto the SD card (or whatever internal storage where you store your photos, downloads, etc.). You can only install it into Termux's directory, which is /data/data/com.termux/files.