Here’s a clear, detailed breakdown of the episode (720p WEBrip quality would refer to the video source, but the story remains the same):

A Swedish Science Thing and the Equation for Toast Original Air Date: May 16, 2019 (Season 2 finale) Proper Story Summary: Main Plot (Sheldon & the Nobel Prize): Sheldon is ecstatic when he learns that two scientists (Gerd Binnig and Heinrich Rohrer) have won the Nobel Prize in Physics for inventing the Scanning Tunneling Microscope—a topic he had just been studying. Convinced that he is destined for Stockholm himself, Sheldon meticulously prepares his family for his future Nobel banquet speech, practicing his "humble yet brilliant" acceptance. However, the episode ends with a reality check: while Sheldon dreams of glory, his mother Mary grounds him by reminding him of the hard work ahead, not just fame.

Georgie asks his father George for advice on how to be a "best man" at a friend's wedding. George teaches him that a good toast is simple, sincere, and not about showing off. Georgie ultimately delivers a surprisingly heartfelt and well-received toast, showing a rare moment of maturity.

Mary continues to feel stifled by Pastor Jeff's rigid leadership at the church. After a disagreement over how to handle a church event, she starts to question whether she belongs there anymore, foreshadowing her later drifting away from that specific congregation.

It sounds like you're looking for a for Young Sheldon Season 2, Episode 22 ("A Swedish Science Thing and the Equation for Toast").