The S&P 500 ticked higher on Wednesday as investors turned their eyes to Nvidia earnings, which could be a make-or-break moment for the bull market.

The broad market index ended the day up 0.24% at 6,481.40, setting a fresh all-time closing high. The Nasdaq Composite closed up 0.21% at 21,590.14, and the Dow Jones Industrial Average gained 147.16 points, or 0.32%, to finish at 45,565.23.

Shares of Nvidia, which account for roughly 8% of the S&P 500 and has the biggest weight in the benchmark according to FactSet data, were little changed.

The market has been largely looking past Trump's unprecedented move to fire Fed Board Governor Lisa Cook from the central bank's board, with U.S. stocks coming off of a lackluster trading session by ending little changed Tuesday.

"Interest rates are on the cusp of being lowered, and earnings are trending higher. In aggregate, inflation, interest rates and earnings trends support a risk-on bias," said Terry Sandven, chief equity strategist at U.S. Bank Asset Management, in an interview with CNBC.

Some individual names managed strong gains despite the muted action in the broader market. MongoDB popped about 38% after the developer data platform topped Wall Street's expectations. Okta jumped more than 1% after its quarterly results and full-year forecast beat consensus estimates.

Both companies cited the demand coming from companies developing artificial intelligence platforms for the strong results. That bodes well for Nvidia, which releases its financial results after the closing bell on Wednesday.

Wall Street has high hopes for Nvidia, which is considered a bellwether in the broader market and a major indicator of AI development. Its earnings could either dampen or propel this year's rally, particularly as the "Magnificent Seven" looks to recover from last week's sell-off.

The chipmaker has beaten earnings expectations in 11 of past 12 quarterly reports, but the stock has had a downbeat post-earnings reaction four of those times, per FactSet.

"The path of least resistance for equities continues to be up, and part of that's driven by favorable sentiment from many technology companies, including Nvidia," Sandven also said. "Our expectation is that you will see a generally favorable report from Nvidia."