Korda, 20, shot four-under-par 68 for an aggregate score of 13-under 288 at the LPGA Taiwan Championship in Taoyuan, finishing two shots clear of Australia's Minjee Lee.
Two birdies, no bogeys and an eagle on the par-five sixth made for a straightforward win after Korda's overnight co-leader, Taiwan's Hsu Wei-ling, fell away with a 74 to finish tied sixth.
Australia's Lee shot 66, her lowest round of the tournament, to rise to second, one stroke ahead of American player Ryann O'Toole who carded 67 to finish third.
Korda was in tears on the 18th green when she spoke to 25-year-old Jessica, a five-time LPGA Tour winner, and other family members at home in the United States via video chat.
"That definitely brought me to tears, seeing everyone lined up there. When I was walking up to 18 I was like 'Oh my gosh Nelly, hold back the tears!'" she said.
The Korda sisters are the daughters of former tennis world number two Petr Korda, who won the Australian Open 20 years ago in 1998.