Can the 'FROM' email address be changed for notifications?

If you set the Notification to only fire when a single record is changed (that is a setting near the bottom), then you have a lot of flexibility for the FROM.  For example it can come from [Last Modified by] or any user field.

Yes, it's in the "Advanced Options" section in the notification configuration. "Advanced Options" is at the bottom of the configuration interface for the notification to modify.

I will add that the From field will send from an unformed email address, there are spaces around the @ symbol. This is because to send an email from a Quick Base server but have it appear to come from your company domain @company.com is called spoofing and looked down upon by the Internet. Most mail exchanges will reject this type of email as this is how virus and malware are spread. The end result is your users cannot hit reply and email you back. In order to do that you have to use the API magix.