Mr Nathan, the founder of Risk Reversal Advisors, said: "I’ve buying bitcoin cash and ethereum.
"Those two seem like ones that have some room to go here, while bitcoin seems to have some technical issues.
"People really want to build on the ones where they think it's cheaper and faster and those are ethereum and bitcoin cash."
Fellow CNBC panellist and trader Karen Finerman added: "Bitcoin cash is more interesting. The discrepancy with bitcoin is there, but the gap will close."
Interest in bitcoin cash surged after the alternative currency to bitcoin was shown to be faster and cheaper to use.
Earlier this week, bitcoin cash rose after BitPay processor announced an integration to provide instant bitcoin to bitcoin cash trades.
Since its launch, bitcoin cash has been adopted by major currency exchanges such as Coinbase, Bitfinex, Bitstamp and ShapeShift
Bitcoin cash was created last year when a group of bitcoin miners announced that they would be "forking" to create a new currency which makes trading faster and easier.
