Even with the U.S.-China trade war still raging, Chinese stocks are on fire.

Increasing trade tensions between the U.S. and China through the back-half of 2018 took a sledgehammer to Chinese shares. Baidu ended the year with a 32 percent loss, while Tencent was down 23 percent, and Alibaba dropped 21 percent.

However, the FXI China large-cap ETF has surged 7 percent in the past three months, while U.S.-listed China-based stocks such as Baidu, Alibaba, Tencent and Sina have rallied by at least 8 percent to begin 2019. And it's Tencent that's flashing a buy signal, says Craig Johnson, chief market technician at Piper Jaffray.

"There's certainly some opportunities to trade here," Johnson said on CNBC's "Trading Nation" on Friday. "If I look at the chart of Tencent, here's a stock that's traded off meaningfully. We've now just reversed the downtrend."

Tencent had plummeted 47 percent from its January peak last year to its trough last October. Since that bottom, it has rallied 35 percent to four-month highs.

A key technical indicator, its moving average convergence divergence (MACD), is also suggesting a bullish lean to the stock, says Johnson. A stock's MACD demonstrates the correlation between a 26-period exponential moving average and a 12-period exponential moving average. When measured against a baseline, the indicator can suggest bullish or bearish momentum.

"When we've seen a MACD buy signal happen like we have right here, we've seen that 30 days later that the stock is typically up almost 13 percent," Johnson explained. "This would be one we'd be buying."