High inflation and rising interest rates have eroded confidence in the economy, triggering a sweeping downturn in the stock market. In fact, the Nasdaq Composite has suffered its worst sell-off in the last 10 years, sending the tech-heavy index deep into bear market territory.

That downturn has undoubtedly left many investors disheartened, but there is a silver lining to the dark cloud hanging over the market. The current situation represents a once-in-a-decade buying opportunity, and excellent stocks like Nvidia (NVDA 0.81%) and Atlassian (TEAM 0.57%) are trading at a fraction of their historical valuations.

Nvidia: A chipmaker shaping the future of technology

Nvidia is a semiconductor company that specializes in graphics and accelerated computing. Its core product is the graphics processing unit (GPU), a chip designed to handle large volumes of data very quickly. Nvidia GPUs have become the gold standard in gaming, entertainment, and complex data center workloads like artificial intelligence (AI). But the company also provides a growing number of subscription software products.

For instance, Nvidia AI Enterprise is a suite of software that helps businesses build and deploy AI applications that address virtually every industry, from autonomous robots in manufacturing facilities to interactive avatars in customer service settings. In a nutshell, Nvidia is a comprehensive provider of cutting-edge computing solutions -- from hardware to software -- and the company is quite literally shaping the future of technology.

In fact, Nvidia has consistently set performance records in the MLPerf benchmarks for AI training and AI inference, and it holds over 90% market share in supercomputer accelerators and workstation graphics, evidencing its technological superiority.

Unfortunately, the macroeconomic environment has caused a significant drop in demand, resulting in disappointing financial results. In the most recent quarter, revenue fell 17% and net income plunged 72% year over year. Worse yet, management expects fourth-quarter revenue in the ballpark of $6 billion, which implies a 21% decline from the prior year.

However, investors need to consider the big picture. Macroeconomic challenges are temporary, meaning the investment thesis is unchanged. In other words, Nvidia is still a best-of-breed semiconductor company chasing a $1 trillion market opportunity. And with shares trading at 15.2 times sales, a discount to the three-year average of 20.3 times sales, right now is a good time to buy this growth stock.

Atlassian: A software company that helps businesses work more efficiently

Atlassian specializes in productivity and team collaboration software. The company is best known for Jira, a family of products that help businesses plan, track, and manage work across teams like development, operations, marketing, and human resources. But its portfolio also includes solutions for IT service management, knowledge management, and visual collaboration.

Atlassian benefits from a somewhat unorthodox go-to-market strategy. Whereas many software vendors rely on a direct sales force, Atlassian relies primarily on self-service sales and word-of-mouth marketing. That strategy has kept its sales and marketing costs low over time, enabling the company to focus on product development. To that end, the Atlassian platform comprises a broad number of easy-to-use products, many of which have achieved a strong market presence.

This year, IT research specialist Gartner recognized Atlassian as a leader in enterprise planning and IT service management software. Better yet, research company G2 named Atlassian the seventh-best software company in the world in 2022 based on its strong market presence and high user satisfaction scores.

Atlassian reported solid financial results in the first quarter of fiscal 2023 (ended Sept. 30). Revenue climbed 31% to $807 million year over year, and free cash flow increased 31% to $76 million. But some investors still rushed to sell the stock, as management lowered full-year revenue guidance in response to macroeconomic headwinds. Fortunately, Atlassian remains well positioned to create value for patient shareholders.

Atlassian combines work management, IT service management, and enterprise planning tools on a single platform. That strategy simplifies operations and reduces costs for customers, and it drives more customer utilization over time. In fact, in spite of macroeconomic headwinds, net revenue retention stayed above 130% in the most recent quarter, indicating that the average customer increased its spend by more than 30% over the past year.

With that in mind, Atlassian puts its addressable market at $29 billion, and management says that figure is expanding at 14% per year. For that reason, investors should have confidence in Atlassian's ability to reaccelerate revenue growth in the future. In the meantime, shares trade at 12.1 times sales, just above the five-year low of 9.9 times, and that creates an excellent buying opportunity.