Nonvolatile memory devices are provided including an integrated circuit substrate and a charge storage pattern on the integrated circuit substrate. The charge storage pattern has a sidewall and a tunnel insulating layer is provided between the charge storage pattern and the integrated circuit substrate. A gate pattern is provided on the charge storage pattern. A blocking insulating layer is provided between the charge storage pattern and the gate pattern. The sidewall of the charge storage pattern includes a first nitrogen doped layer. Related methods of fabricating nonvolatile memory devices are also provided herein.