The 31-year-old reality TV star visited some venues with Harden, 25, on July 4 night, reports tmz.com.
Kardashian and Harden were spotted having dinner at an Asian restaurant, Red 8, in Wynn hotel.
Sources said the pair looked like a couple as they were snuggling side by side during the meal.
According to the report, the two headed to Drai's nightclub, located quite far from the restaurant, after they finished with their dinner.
However, the two were partying up before leaving the hotel as other sources spotted the two spending some time at the Encore Beach Club, in the same hotel where the restaurant is located.
Kardashian and Harden reportedly began to know each other since the Houston Rockets player served as one of the coaches during rapper Kanye West's birthday tournament at Staples Center last month.