Simulating High-Side N-Channel Bootstrapping in LTspice
The main thing I notice when looking at your LTspice schematic is that none of the semiconductors (MOSFET, BJT, and diode) have a specific part number defined.  What this does is force the SPICE engine to use all default parameters for these devices.  For a BJT and diode under generic use, it's usually not that big of a deal.  However, with the MOSFET there is a huge problem.  The default MOSFET models are for modeling integrated circuit (i.e. &quot;monolithic&quot;) MOSFETs.  First, they are not suited for modeling discrete VDMOS FETs, due to them having a completely different structure.  Second, their default value for the Vto parameter (zero-bias threshold voltage) is set to zero, which is likely where your specific problems are stemming from.
To fix this, right-click on the symbol for the NMOS and then click the Pick New MOSFET button.  A list of parts shows up.  Since the video you linked shows an IRF1405 stuffed in the breadboard, let's try to find that.  Click on the Part No. column header as shown to sort by part number.



Then, we can scroll to find the IRF1405 listed in alphabetical order.  We can either double-click the line for IRF1405, or single-click it and then press the OK button to select it.


A good rule of thumb is to always avoid default semiconductor models, not just the MOSFET ones.  You do that by always selecting a part number, even if you just need something generic to get the thing rolling.  Using parts with non-default parameters can help avoid convergence problems and also model more real-world effects.  Whenever I make a simulation using discrete semiconductors which have a non-specialized purpose, I typically select the following built-in LTspice model for each device type:
Silicon PN Diode -&gt; 1N4148
Schottky Diode   -&gt; BAT54
2.0V-ish LED     -&gt; QTLP690C
3.5V-ish LED     -&gt; NSCW100
NPN BJT          -&gt; 2N3904
PNP BJT          -&gt; 2N3906
N-chan JFET      -&gt; 2N3819
P-chan JFET      -&gt; 2N5460
N-chan VDMOS FET -&gt; 2N7002
P-chan VDMOS FET -&gt; BSS84

Therefore, I would also change your NPN transistor to 2N3904 and your silicon diode to 1N4148.