This question can trigger hours of discussion. To keep it simple, I'll address only non-probate property. Non-probate assets are those that are not controlled by your will or trust. Assets that are controlled by contractual succession like a beneficiary designation on your life insurance policy, or real property titled as joint tenants with rights of survivorship are non-probate assets.
That leaves property like personal possessions, cars, property owned as tenants in common, family heirlooms, and liquid assets like cash and securities. In most cases these are non-probate assets and when not provided for in a will or trust (meaning the decedent died "intestate") are subject to the state's succession rules in NRS 134.
Nevada is a community property state. That means that most property acquired by a couple during marriage is community property and is split down the middle. The surviving spouse receives his or her share as their sole and separate property. According to NRS 123.250, the remaining share will also go to the surviving spouse unless some other testamentary disposition has been made. That's important because if the decedent spouse had children from a previous marriage, those children will have no legal right to the community property portion of their deceased parent's property. That is, unless a will and/or trust is in place to direct differently. If that is an undesirable result, then estate planning in advance will resolve that.
If the decedent (meaning deceased) spouse had any separate property of their own, that property is treated differently. This includes assets acquired before a second marriage that haven't been commingled and mixed in with the couple's community property. After debts are paid, the remaining amount is now subject to succession rules. Different circumstances dictate different treatments:
If the decedent spouse left behind only his or her surviving spouse and one child, then the property will be split evenly between the two. If there is a surviving spouse and more than one child, then the surviving spouse receives one third of the separate property, with the kids receiving equal shares of the rest.
Finally, if the person who passes away is single, either having never been married or was predeceased by his or her spouse, but leaves behind one child, then that child receives the entire estate. If there are multiple children, then the children share equally. The shares are the same no matter if the child is alive or dead, so long as a deceased child left behind children of their own, who would receive their parent's share in equal shares among themselves.
This is a very simplistic breakdown of Nevada's succession statutes and ignores less common scenarios. The point of this though is to show that what the state has planned for you and your family may not be what you have in mind. This is especially true for the increasingly common second marriages where kids from a previous marriage stand to lose quite a bit if proper planning is not made.