Sudden increase in smell w or wo nausea, smoker, essure, no headache. causes?

Migraine equivalent?: I'm unable to interpret all of your question (essure?). If you mean your sense of smell is heightened and you have nausea at times, you may be having a partial migraine phenomenon without the headache. Some doctors refer to this phenomenon as "migraine equivalent." Much less likely would be an unusual type of seizure originating in the temporal lobe of the brain.