The phrase "next chart" means the upcoming or following graph or diagram. It refers to the visual representation of information that comes after the current one. Full definition
The next chart from Charles Schwab's Jeffrey Kleintop shows that stocks followed similar trajectories after the Cuban Missile Crisis (left hand side) and the Invasion of Iraq in 2003 (right hand side). (businessinsider.com)
Everything we've talked about so far is captured nicely in this next chart from JP Morgan Asset Management's David Kelly, which is on a log scale and includes annotations of major world events. (businessinsider.com)
The next chart of 3M adds capital gains to dividends: (seekingalpha.com)