To replace a node in Nuke, simply hold down Ctrl/Cmd and create a new node. See below for more details.
1. | In the Node Graph, select the node you want to replace. |
2. | Hold down Ctrl (Cmd on a Mac) and create a new node using the Toolbar, a right-click menu, or the Tab menu. To replace a node with the Tab menu, press the Tab key first, then hold down Ctrl/Cmd when selecting the new node. |
The new node replaces the selected node in the Node Graph.
NOTE: Note that you cannot replace nodes in this manner if you are using a hotkey (such as B for the Blur node) to create the new node.