Trying to use an LCD 1602 to display, but I don't have a 10 KOhm potentiometer I'm following this tutorial page and I don't have a 10k ohm potentiometer on hand. Could I replace it with resistors to simulate a manual setting and replace the resistors to adjust to a new settings.

From what I was reading this pin is for contrast and I'm sure I could manually set the contrast once and be happy with it for quick prototyping. I'll be ordering a 10k ohm potentiometer on Monday.
Yes. All a potentiometer is, is two resistors end to end.  The "wiper" is the join between the two resistors.

It doesn't matter too much what value potentiometer (and hence what value resistors) you use, as long as it's "around" the 10kΩ mark (100kΩ should be fine, 50kΩ, 1kΩ etc - anything below 1kΩ may not work) - what matters is the ratio of the values of the resistor.