I am retiring at the end of 2018. I hope to move to the Pacific Northwest, preferably Oregon. I currently reside and work in VA. I will receive a one time large deferred compensation benefit from my VA employer in early 2019. Can I move to Washington State for part of the year to avoid paying income tax in either VA or Or on this lump sum?
You'll find Oregon's definitions of residency (for tax purposes) on page 7 of this reference: http://www.oregon.gov/DOR/forms/FormsPubs/publication-or-40-np_101-045_2016.pdf
You're not subject to OR income tax until you become an OR resident.
Payments from deferred compensation plans are taxed based on the state of residence at the time of the deferral into the deferred compensation plan unless you elect installment payments over 10 or more years. If you lived in Virginia when deferrals were credited to your account in the deferred compensation plan, you will be taxed by Virginia when the lump sum payment is made from the deferred compensation plan regardless of where you are living at the time of the payment.