Texas Instruments provides a PSpice model for the TL494. While PSpice models often work in LTspice, they require conversion. Download the .lib or .cir file from TI’s website, then use the .include directive in LTspice.
LTspice does include a TL494 model by default. You have three options: tl494 ltspice
.MODEL SW SW(RON=0.1 ROFF=1Meg VT=0.5 VH=0.1) Texas Instruments provides a PSpice model for the TL494
.ENDS TL494
The biggest challenge is that LTSpice does not include a native TL494 model in its standard library. You have three options: tl494 ltspice