The very fact that the rumour is out there means there could be fire where there is smoke, but until Pettersson hits free agency and begins talking with teams, it's all speculation and whispers from various league sources.
One thing that was absent from the discussion was further details about Pettersson's future in Vancouver, as it appears as though no discussions about a major extension have come to fruition. In his rookie campaign, Bedard has lit the NHL world on fire, and the very thought of both Petterson and Nylander teaming up with the young star makes Chicago an interesting destination, so while it doesn't appear likely at this point, we can never say never about the future of an NHL player.
Ultimately, Pettersson is making himself one of the most valuable players in the NHL with his performances over the last 18 months, and when he becomes a free agent, there will be plenty of attention coming his way, meaning that every team, including Chicago will no doubt be chasing his services.