I have a company in New Hampshire, but also hired independent contractors in other states such as Maine. Does this create tax nexus in those states in which I would be liable for sales tax?

Generally speaking, hiring independent contractors typically creates tax nexus as it helps your organization to create or maintain a marketplace in that location. It may vary by state law, but that is the general guidance to follow. This is further supported by the US Supreme Court decision of Tyler Pipe in 1987. In Maine, activities conducted on behalf of a foreign corporation by an independent contractor that are more than de minimis in nature and that are significantly associated with the foreign corporation's ability to establish and maintain a market in Maine will be considered as creating tax nexus.