Do I need to send a 750B along with EB2-NIW

In general EB2 requires labor certification, and it is usually done by a sponsoring company. However if you self-petition for an EB2 in the NIW category, you can request to do without the labor certification process.  Therefore EB2-NIW applications may not contain a 750B form (actually the new form is ETA9089 instead of 750). You can attach a filled 9089 along with the i-140 packet. In this case you sign the form (not the employer).