Nancy K. Nichols (born 1942) is an applied mathematician and numerical analyst whose research concerns numerical methods for differential equations, linear algebra, and control theory, and data assimilation. She is a professor in the Department of Mathematics and Statistics at the University of Reading.
In 2012, a conference was held at Reading in honour of Nichols' 70th birthday.Nichols was elected as a Fellow of the Society for Industrial and Applied Mathematics in 2014, "for contributions to the numerical analysis of systems, control, and data assimilation".