What Ni offers. Ni base types are able to consider the potential outcome of a situation, and use this to reign in on the impulse of the Se base type. They are able to bring an element of wisdom to the Se base's total certainty in what the Se base type believes is basically the Truth (potentially more relevant to the SLE than to the SEE). The Ni base type knows when it's a good idea for the Se base type to hold back, and offers counsel at these times, which the Se base type, who trusts the Ni base type in their confidence about the future, willingly accepts.
What Se offers. Se base types are able to kick start Ni base types into action in a way which keeps them motivated for a prolonged amount of time. They can put an end to the Ni base type's dithering in their thinking, and will often quell unnecessary uncertainty, or haziness when a decision must be made. The Se base type knows when it's a good idea to act, and the Ni base type will gladly accept the Se base type's plan of action, knowing (using their Ni) that it will be fruitful in the long run.