It may seem like Amazon is unstoppable when it comes to e-commerce, but another retailer is hot on its tail: Walmart.

Shares of the retail giant gained as much as 4 percent Tuesday after the company topped Street estimates for earnings and revenue. The company also said that online sales grew 43 percent during the all-important holiday quarter.

Walmart stock has been the clear winner over archrival Amazon in the past six months, with shares rising 5 percent versus Amazon's 14 percent slide.

While some might see Walmart's gain as Amazon's loss and vice-versa, Oppenheimer's Ari Wald and Chantico Global's Gina Sanchez argue that these stocks can co-exist, and that there's upside for each one in the long term.

"I don't think it's an 'either or' thing when discussing these two stocks. In fact, we think they both can work higher together … [we have] both Walmart and Amazon.com on our S&P 500 buy list," Wald said Tuesday on CNBC's "Trading Nation."

Wald likes Walmart at current levels because he says the stock chart indicates it is firmly in an uptrend. He noted that the stock is "coming into an important test of its trend of lower highs dating back to early 2018" and that investors should "stick with this strength" in order to play "the breakout based on good relative strength."

He also says the retailer is beating its benchmark as well as the broader market, which is a sign of positive momentum. In the last three months, shares of Walmart have gained nearly 7 percent versus the S&P's 4 percent gain. Consumer staple stocks, on the other hand, have shed just over 2 percent.

Despite Amazon's recent weakness, Wald is expecting the stock to soon turn a corner based on the favorable backdrop. He believes that in a "lower-growth world," investors will give a premium to higher-growth companies, like Amazon, which is trading above $1,627.

The key number he's watching is $1,780, which has been a resistance level for the stock in recent months. From a technical standpoint, that means that the stock has repeatedly reached that level, but that it has failed to break through and bounce higher from that price.

Wald notes that Amazon is "building this base below $1,780 resistance," which he says means it will "ultimately break higher."

Like Wald, Chantico Global's Gina Sanchez believes investors can own both Walmart and Amazon.

When it comes to Walmart, she specifically likes the sustained growth the company has shown in e-commerce sales.

"Walmart has been putting a significant amount of effort and money behind building out their online services and they're starting to see some returns from that," she said.

Sanchez also likes Amazon for the long term, attributing much of the recent weakness to a temporary slowdown in the company's lucrative web services segment.

"Amazon Web Services has actually been a huge grower for them, and that whole cloud area is actually slowing a bit. You're seeing that in the chip stocks, you're seeing that play out in other spaces, so while that was a huge benefit for Amazon, it's probably just sort of becoming a little more of a laggard. But long term we do think that that's a great play for Amazon, and so I wouldn't count Amazon out here by any stretch of the imagination," she said.

Amazon is currently trading in a bear market, with shares falling just over 20 percent from their 52-week intraday high of $2,050.50 from September.