There are two methods for drawing a nitrile (CN) group with the JME Editor. One generates a cleaner looking structure, showing the group as "CN", but does not generate a chemically correct "SMILES" structure. It uses the "X" button to insert the CN in the structure.
The second, chemically correct, method shows the CN group as a carbon with a triple bond to nitrogen, and the "SMILES" string generated can be graded by the computer. You should use the second method in drawing any organic compound containing a CN group.
(Using the X button for CN)
(Using C with triple bond to N)