nzbget: url: http://nzbget:1234@localhost:6789/xmlrpc category: movies
nzbget: url: ... category: ... priority: ... top: ...
By setting entry category you can override / specify nzbget category per item. To set it you can use plugins like set, manipulate. top stands for append to top, each nzb will be added to the top of the queue. Further you can modify the Priority which is used for a file by nzbget with the priority parameter, the valid values are -100 (lowest) to 100 (highest). More information can be found in the [API reference].
See this recipe for example how to set category from a series name.