At 7:13 of the first period in the Predators/Penguins game, Pittsburgh requested a Coach's Challenge to review whether Filip Forsberg was offside prior to Nashville's goal.
After reviewing all available replays and consulting with the Linesmen, NHL Hockey Operations staff determined that Forsberg preceded the puck into the attacking zone, nor did he have possession and control before crossing the blue line. According to Rule 78.7, "The standard for overturning the call in the event of a 'GOAL' call on the ice is that the Toronto Video Room, after reviewing any and all available replays and consulting with the Linesman, determines that one or more Players on the attacking team preceded the puck into the attacking zone prior to the goal being scored and that, as a result, the play should have been stopped for an "Off-side" infraction; where this standard is met, the goal will be disallowed."
Therefore the original call is overturned - no goal Nashville Predators.
The clock is re-set to show 13:02 (6:58 elapsed time), when the off-side infraction occurred.
Since the Coach's Challenge resulted in the original call being overturned, the Penguins retain their time-out.