World Cup Nordic races are available live online via a semi-questionable website known as FromSport.com. They have a lot of pop-ups but I’ve been using the site for years now and never encountered any real problems besides the ads. Races typically occur on the weekends between ~5:00am and 9:00am EST.
World Cup Biathlon races are available live online as well as anytime after the event ends. The website is the IBU Eurovision.