2. Warren Spahn - 91.8 WAR
In the number 2 spot in the Braves' all-time starting rotation is Warren Spahn who put up 91.8 rWAR from 1942 to 1964. Spahn's 356 wins with the Braves is the most in franchise history. In over 5,000 innings, Spahn posted a 3.05 ERA and 3.43 FIP. Spahn wasn't known for his ability to strike out batters, but the longevity of his career still allowed him to strike out 2493 batters with the Braves to put him third all-time on the Braves' rankings there.
There is no way to know for sure, but it does seem likely that Spahn would have added to his totals significantly and even challenged some league-wide all-time records had World War II not broken out during the early portion of his career. Spahn would enlist like many players and missed three full seasons while serving with distinction in the US Army. Before returning to the Braves, Spahn would be awarded a Purple Heart and a Bronze Star for his time in the war and credited his time in the military for preparing him to be a successful player afterward.
1. Kid Nichols - 107.4 WAR
A lot of Braves fans are probably not familiar with the top player on this list, but that is largely due to how long ago he played. Kid Nichols pitched for the Braves from 1890 to 1901 and put up some video game end boss numbers during that time. In his 502 starts for the Braves, he threw 476 complete games with a 3.00 ERA and 3.59 FIP. Nichols was an absolute workhorse for the Braves during his career with seven seasons with 30+ wins and 11 seasons with north of 300 innings pitched.
Nichols was great and is a worthy addition to the Braves' all-time starting rotation, but his case does highlight a fundamental problem with comparing WAR across eras. The game has baseball has changed so much over time and the era Nichols played in allowed him to pitch entire games on the regular against hitters who were largely not remotely comparable to who the other guys on this list had to go against. In the end, context does matter, but Nichols does deserve some more love for his Hall of Fame career nonetheless.