The star, who was previously married to Liam Gallagher, tied the knot with Stephen Haines at luxury hotel Cliveden House in Berkshire, England.
Sharing two photos on Instagram, which were captioned with ring and heart emojis, she wrote, "I do..."
In the first picture, the couple smiled for the camera with the venue visible in the background while, in the second, Nicole's stunning fitted dress, which had a tulle train attached at the waist, could be seen in full as the pair walked hand-in-hand down the aisle.
The "Never Ever" singer thanked designer Alida Herbst for her dress and praised her hair and make-up team.
She wrote, "Thank you to my fabulous A team @celena_hancock @patrickwilson #hair #makeup I love you both (heart emoji) @alida.herbst for making me my beautiful dress I LOVE IT!! You all made me feel truly amazing!"
"And @charliedailey for the gorgeous pictures. (sic)"
The couple's big day came 18 months after they revealed they had welcomed daughter Skipper Hudson into the world, having kept Nicole's pregnancy under wraps throughout.
Not only did the star hide her pregnancy from fans but also from family and friends. She said it was "SOOOOO difficult" and she felt relieved to finally announce the newest addition to her family last year. "Stephen & Gene are besotted!!! I'm SOOO HAPPY!!" she gushed, referring to husband and son from her previous marriage.