Chia. I agree with dr. Ali -- chia seeds have been eaten safely for years, and even the ancient aztecs enjoyed them. Clinical studies show they may reduce blood pressure, hb a1c, fibrinogen, and high-sensitivity c-reactive protein -- making them potentially heart-protective. http://tinyurl.com/lts5d79 i can find no mention of palpitations. Please work with your doctor to find the cause.
Chia seeds. This is a flowering plant in the mint family. Its contents are similar to flax or sesame seeds. Unlikely that it would cause palpitations, to my knowledge. You might want to ask your pcp for workup to rule out health issues that could attribute to nervousness.