Nebraska does not have a law against open carry in public, hence Nebraska is an open carry state. However there is no state statute specifically "allowing" it and there is no state pre-emption in this regard either so local law can be more strict than the state law. The best thing to do would be to check your city's ordinances to make sure there is no provision banning open carry as well as your county rules in this regard if applicable. Omaha for instance bans open carry for the average Joe gun owner unless you take a class and get their "Firearm ID Card" which will then permit you to open carry within Omaha city limits.
Even if you have cleared all the above, remember that if some "concerned" citizen sees you walking around WalMart with a handgun on your hip and decides to make a "man with gun" 911 call, the cops will show up and you will be subjected to some or all of the following: questioned, harassed,disarmed, shoved facedown on the pavement, arrested, interrogated, charged with disorderly conduct/disturbing the peace etc.
It will all depend on the mood or mindset the police officer has at the time as well as their own interpretation of certain rules/laws/directives etc. and the city's policy on handling open carrying gun folks.
Keep in mind that your behavior while carrying openly in public will also be taken into account. Someone might just call 911 because you are having a "lively" debate with anyone or even a friend while carrying a sidearm. For instance you and a friend/family member are in a grocery store and your chatting about politics while doing your shopping and you two get a bid loud and passionate about a certain issue where there is disagreement and some granny or soccer mom takes it the wrong way and calls 911 because your having a heated debate and carrying a gun. Another scenario: Your buying gas at the gas station and for some reason the fuel station malfunctions and shorts you money. You go into the store and the clerk is less than helpful and basically tells you that there is no way your money can be redeemed or something like that. So normally you'd blow a gasket and give the clerk a piece of your mind but now your carrying a gun visible to everyone and you best bite your tongue and go with calling their corporate office. There are plenty of scenarios like this one where you may get angry in a social setting and that while carrying an openly visible pistol on your hip probably wouldn't be a good idea. It may limit your options and it should/will alter your behavior unless you want to explain yourself to a police officer. Such a situation can spiral out of control in regards to unwarranted charges from the police. Who knows they could charge you with assault because your behavior was interpreted as threatening.
I'm not a lawyer, just my two cents.