Is notes receivable a current asset?

Yes, notes receivable is a current asset, so long as payment is expected to be received within one year of being incurred. 

Current assets are any assets that can be converted into cash within a period of one year. This counts products that are sold for cash as well as resources that are consumed, used, or exhausted through regular business operations that are expected to provide a cash value return within a single year. Current assets reflect the ability of a company to pay its short term outstanding liabilities and fund day-to-day operations.